and bear much resemblance to each other, which will be apparent from the illustration (fig. 115).

The intrinsic muscles are attached to the seventh bronchial ring, which is soft and cartilaginous; where the bronchial rings change their character is a constriction of the membrana tympaniformis; it is, however, of equal breadth before and after the change. In Podargus Cuvieri there is a further approach to the purely bronchial syrinx of Steatornis. The

FIG. 114. SYRINX OF Egotheles (AFTER BEDDARD).

FIG. 115. SYRINX OF Batrachostomus (AFTER BEDDARD).

first two bronchial rings are complete. These and the fourteen following are closely applied to each other and ossified. The intrinsic muscles are attached to the last of this series. Egotheles really belongs to this section of the Caprimulgi, though the intrinsic muscles are attached very high up upon the bronchi; but the two rings immediately preceding the attachment are complete rings. The final development of the bronchial syrinx is seen in Steatornis (see fig. 48, p. 69), where all the rings in front of the attachment of the intrinsic muscles low down upon the bronchi are closed and complete rings, as in Crotophaga.

The tensor patagii shows certain differences among the goatsuckers. In the genera Caprimulgus, Nyctidromus, and Chordeiles there is a biceps slip, absent in the rest. Of these three genera the arrangement of the tendon is shown

in the annexed cut (fig. 116). Steatornis, as will be seen. (fig. 117), hardly differs, and Podargus agrees with it. In Egotheles there is a slight difference in that there is hardly any trace of the wristward branch of the tendon. Steatornis has an expansor secundariorum, apparently absent among the other genera. The muscle is attached to the teres by its long tendon. The insertion of the deltoid is extensive, and it receives a tendon from the scapula. In many Caprimulgidæ the biceps is split for some distance before its insertion, the bifidity even invading the muscle itself and not being

limited to its tendon. In Podargus FÜRBRINGER describes a special slip of rhomboideus profundus, arising separately from ilium. The anconaus has a tendinous humeral head. In the thigh the muscle formula is either AXY- (most Caprimulgi) or XY- (Steatornis). The tibialis anticus tendon of Podargus is double. The glutæus I. extends over biceps in Nyctidromus, &c., not in Egotheles, No glutæus V. There are sometimes both and sometimes only one of the two peroneals present. In Steatornis and Egotheles only the brevis is to be found, in Nyctidromus only the longus; in Podargus both.

The goatsuckers have by no means a uniform skull structure.

In Caprimulgus1 the skull may be termed schizognathous. The palatines are enormously expanded, and between their posterior extremities (not indicated in the figure) are a small anterior and posterior medio-palatine, a state of affairs recalling the Picidæ (q.v.) The vomer is a long bone, distinctly paired in the young bird, rounded in front. It articulates

FIG. 118. SKULL OF Caprimulgus (AFTER HUXLEY).

Pmx, premaxilla; Map, maxillo-palatiue; Vo, vomer; Pl, palatine; Pt, pterygoid.

with the hook-like maxillo-palatines. Each of the latter is connected by a ligament with the internal forward process of the palatine of its own side, the hinder part of which is largely ossified. The basipterygoid processes are well developed. The lacrymal is large and binds upon the zygoma." The ectethmoids are attached to the broad outer flange of the palatines by a cartilaginous prolongation.

1 PARKER, On the Structure and Development of the Bird's Skull,' Linn. Tr. (2), i.

In Chordeiles the skull is much upon the same plan, but the maxillo-palatines meet in the middle line, and may even become ankylosed.

The skull is thus desmognathous, in fact. In C. virginianus, however, the bones do not meet.

The skull of Nyctibius jamaicensis (see fig. 119), described by HUXLEY, is not widely different from that of Caprimulgus. The ligaments which unite the inner angle of the

palatine to the maxillo-palatines are, however, completely ossified.

In Podargus the skull is completely doubly desmognathous. The basipterygoid processes are quite rudimentary. There are two small azygous vomers. The palatines have coalesced in the middle line. The lacrymal is small, if not absent.

The skull of Steatornis has been described, with figures,

1 SHUFELDT, On the Osteology of the Trochilidæ,' &c., P. Z. S. 1885, p. 891.

PARKER, loc. cit. p. 124 (with figs. on Pl. xxiii.)

by GARROD,' and more recently and more fully (also with illustration) by PARKER.2 The skull is quite owl-like in general aspect with its decurved beak, and in the equality between greatest length and greatest breadth. The lacrymal is very small and is ankylosed to the orbital wall. The

Pl

Mxp

Pmx

FIG. 121. SKULL OF Podargus (AFTER HUXLEY). LETTERS
AS IN FIG. 118.

maxillo-palatines are completely fused across the middle line, the skull being desmognathous. The palatines also in their middle part meet across the middle line. The vomer is divided into two parts, one lying behind the other. The anterior part is small, like the posterior part; they both measure 5.5 mm. The posterior vomer is probably the equivalent of the medio-palatine of Caprimulgus and other birds. The basipterygoid processes are well developed.

The

1

On some Points in the Anatomy of Steatornis,' P. Z. S. 1873, p. 526. 2. On the Osteology of Steatornis caripensis,' ibid. 1889, p. 161.