forms enables me to supplement, and, as I believe, to improve these, and accordingly the following systematic sketch of paleozoic Arachnida has been prepared, into which have been thrown such suggestions and new facts as have come to hand.

ORDER ANTHRACOMARTI Karsch.

Body more or less depressed, the cephalothorax and abdomen distinctly separable. Cephalothorax frequently made up in large part of pedigerous segments more or less wedge-shaped, and visible above as well as below, the arrangement of which corresponds to that of the сохӕ. The abdomen forms a single mass, and is composed of a variable number of visible segments, ranging from four to nine. Palpi not much longer than the legs, simply terminated.

Fam. ARTHROLYCOSIDE Harger.

Cephalothorax orbicular, twice as large as the abdomen. Cox radiating from a central pit. Abdomen oval, much narrower at base than the cephalothorax, with no longitudinal sculpturing, and composed of seven segments. No abdominal appendages.

ARTHROLYCOSA Harger.

Arthrolycosa antiqua Harger, Amer. Journ. Sc. Arts, (3,) vii. 219– 223 (fig.), 1874. Mazon Creek, Illinois.

In his description of this arachnid, Harger inclines to the belief that the terminal segment of the palpus is chelate. He says (loc. cit.): "The third [joint] is broken near its proximal articulation, and the connection of this appendage with what seems to be its distal cheliform segment is unfortunately imperfect. This segment is also poorly preserved, and the articulation of its digit is only to be seen with a good magnifier and in a certain light. . . . I do not, however, consider the forcipulate character of this segment beyond a doubt. It is perhaps not improbable that it may have been modified much as in the males of ordinary spiders, and not truly forcipulate."

Having reason, by its undoubted relationship to other forms of Anthracomarti, to doubt the forcipulate character of the palpus, of which Harger speaks so doubtfully, Professor Marsh kindly permitted me to study the type in Yale College Museum, and I find on close examination that not only is the joint in question not chelate, but it terminates by a straight, transverse suture, and is followed by a portion of another, apparently short, terminal joint.

Fam. POLIOCHERIDÆ nov. fam.

Cephalothorax quadrate, not much smaller than the abdomen. Coxæ radiating (apparently) from a median line. Abdomen rounded, of equal breadth with the cephalothorax, with very indistinct or no longitudinal sculpturing, and composed of only four segments, of which the basal is very short. No abdominal appendages.

POLIOCHERA nov. gen.

Cephalothorax scarcely longer than broad, slightly narrowing anteriorly, the front square. Legs stout, moderately long. Abdomen full, at base as broad as the cephalothorax, broadening slightly behind, fully rounded, the first segment about one third the length of the others, which are equal.

Poliochera punctulata nov. sp. Body minutely, deeply and uniformly punctate throughout, excepting on the narrow first abdominal segment, which is smooth. Legs similarly punctate. Length 15 mm., greatest breadth 7.5 mm. Mazon Creek, Illinois (R. D. Lacoe, No. 1845). A fuller description and figure will be given at another time.

Fam. ARCHITARBOIDÆ Karsch.

Cephalothorax of variable form, but at least half as large as the abdomen. Coxæ radiating from a middle point or line, or from a triangular sternal piece, its base on the abdominal margin. Abdomen orbicular or oval, at base as broad or nearly as broad as the cephalothorax, with a lateral ridge on each side converging toward the anus, the surface moderately smooth; segments seven to nine in number, the basal ones visible below, though often extremely shortened in the middle; no abdominal appendages.

GERAPHRYNUS nov. gen.

Cephalothorax fusiform, angulated in front, nearly as large as the abdomen. Coxæ radiating from a median line. Palpi slenderer than the legs, longer than the cephalothorax, springing from its extreme front and of uniform size throughout. Abdomen subfusiform, composed of nine segments, rounded behind, with no constriction at the base; a large triangular post-thoracic plate, crowding the middle of the first five short segments out of a straight transverse line. Readily distinguished from Architarbus by its produced and angulate cephalo

thorax.

Geraphrynus carbonarius nov. sp. Cephalothorax faintly punctu

late, its posterior portion and the post-thoracic plate more distinctly, while the abdomen is profusely and rather sparingly punctate. Length 20 mm. Greatest breadth 10 mm. Mazon Creek, Ill. (Coll. R. D. Lacoe, No. 1701.) A fuller description and figure will be given at another time.

The specimen is interesting as preserving very completely the left palpus.

ARCHITARBUS Scudder.

Cephalothorax orbicular, broadly rounded in front, much smaller than the abdomen, but not separated from it by a marked lateral constriction. Coxæ radiating from a central pit. Abdomen oval, composed of nine segments, of which those on the basal half are very much shorter than the others, and on the dorsal surface are forced still more closely together by the large post-thoracic plate.

Architarbus rotundatus Scudder, Worth. Geol. Ill., iii. 568, fig. 4, 1868. Mazon Creek, Ill.

Architarbus subovalis Woodward, Geol. Mag., ix. 385-387, pl. 9, fig. 1, 1, 1872. Lancashire, England. Here probably belongs Curculioides Ansticii Buckl. Geol., ii. 76, pl. 46", fig. 1, 1837. Coalbrookdale, England.

Architarbus silesiacus Roemer, Jahresb. schles. Gesellsch. vaterl. Cult., lvi. 54, 55, 1879. Glatz, Silesia.

ANTHRACOMARTUS Karsch.

Cephalothorax quadrate, the front square or scarcely convex, about half the size of the abdomen; coxæ radiating from a broad triangular sternal plate, the base of which forms the posterior margin. Sides of the body constricted so as to show a distinct though generally slight separation of cephalothorax and abdomen. Abdomen orbicular, composed of seven segments of similar length throughout.

Anthracomartus Völkelianus Karsch, Zeitschr. deutsch. geol. Gesellsch., 1882, pp. 556-561, pl. 21, figs. 1, 2. Neurode, Silesia. Anthracomartus Krejčii Kušta, Sitzungsb. böhm. Gesellsch. Wiss., October 12, 1883, pl., figs. 1-3, 1883. Rakonitz, Bohemia.

Anthracomartus trilobitus nov. sp. Sides of the cephalothorax angulated in the middle of the posterior half, behind which it narrows rapidly, showing a very marked constriction between it and the abdomen. The latter of equal length and width, broadest behind the middle, and furnished with a marginal flange nearly as broad as the lateral fields. Whole body delicately and uniformly punctate. Length 17.5 mm.; greatest width 11.25 mm. Fayetteville, Ark. VOL. XX. (N. S. XII.)

2

This interesting species was found in some abundance by Rev. F. S. Harvey in the subconglomerate coal measures about six miles northeast of Fayetteville. It differs from all the other species in the remarkable posterior narrowing of the cephalothorax. A fuller description and figure will be given at another time.

Anthracomartus pustulatus nov. sp. Cephalothorax narrowing somewhat forward. Abdomen longer than broad, oval, broadest in the middle, the longitudinal ridges converging regularly and considerably in straight lines, the whole surface of body closely covered with very irregularly polygonal sunken cells, giving the whole body a pustulate appearance. Length 15 mm.; greatest breadth 7.5 mm. Mazon Creek, Ill.

This species was received from Mr. R. D. Lacoe (No. 1752), and differs conspicuously in its rough surface structure from all other species. A fuller description is deferred.

Fam. EOPHRYNOIDÆ Karsch.

Cephalothorax quadrate, narrowing strongly in front, or triangular, less than one third the size of the full abdomen, broken dorsally into many plates. Coxæ radiating from a median furrow. Abdomen ovate orbicular, much broader than the cephalothorax, from which it is separated laterally by a distinct constriction; segments nine or ten in number, some of the basal segments obscured below, the dorsal plates either broken by irregular longitudinal sutures into one median and two lateral fields, or furnished with many longitudinal series of stout tubercles, or both; the penultimate and antepenultimate segments bearing lateral terminal spines.

KREISCHERIA Geinitz.

Cephalothorax subquadrate, with three large median plates, one in front and two behind, and on each side three smaller lateral plates. Dorsum of abdomen broken by oblique sutures, crossing each segment laterally subparallel to the lateral margin, into a median and lateral fields, of which the median is about as large as the combined lateral fields.

Kreischeria Wiedei Geinitz, Zeitschr. deutsch. geol. Gesellsch., 1882, pp. 238-242, pl. 14, figs 1, 2. Zwickau, Saxony.

This species was referred correctly by Geinitz to the vicinity of Eophrynus, but by Karsch considered as belonging to the Opiliones in the neighborhood of Trogulus. The structure of the cephalothorax, though very different in general appearance from that of Eophrynus,

is essentially identical with it, and the abdomen only differs in essential points from that of Eophrynus in characters which ally it to the Architarboida.

EOPHRYNUS Woodward.

Cephalothorax triangular; its dorsal surface tumid, completely broken into great tuberculate bosses, arranged in a lateral row down either side and a median row dividing in two at the posterior margin. Dorsal surface of abdomen with two lateral rows of large rounded tubercles and a median row of large stellate tubercles, besides being sometimes divided by longitudinal sutures into median and lateral fields.

Eophrynus Prestvicii Woodward, Geol. Mag., viii. 385-387, pl. 11, figs. 1, 2, 1871. Curculioides Prestvicii Buckland, Geol., ii. 76, 77, pl. 46", fig. 2, 1837. Coalbrookdale and Dudley, England.

The discovery of new remains of this curious arachnid led Mr. Woodward to notice the incorrect reference of similar remains by Buckland and Samouelle to the Coleoptera. As stated above, it seems probable that the other species referred in the same place to the Coleoptera will prove to be an Architarbus. Woodward neither figures nor makes mention of any fracture of the dorsal plates in his very excellently preserved specimen; but as this exists in the next species, it would seem probable that they might have been overlooked.

Eophrynus Salmi Stur, Abhandl. geol. Reichsanst., viii. ii, p. v, note (fig.), 1877. Ostrau, Moravia.

The generic name is incorrectly spelled Euphrynus.

ORDER PEDIPALPI Latreille.

GERALINURA nov. gen.

Cephalothorax ovate, the front rounded, one third as broad as hinder portion. Palpi large and robust, with interior spines. First two pairs of legs slender, the hinder stout and broad. Abdomen composed of nine joints, the basal three rather short, the others subequal and longer. Postabdomen much as in Thelyphonus.

Geralinura carbonaria nov. sp.

Hinder legs three times as stout as the front pairs, the fourth much longer than the third. Abdomen about twice as long as broad. Postabdomen composed first of two joints together half as long as broad, one third as broad as the abdomen, next of a single quadrate joint, followed by the thread, about one fourth or one fifth as broad, of unknown length, with numerous