8. Coluber constrictor, Linnæus (male). Black Snake. May 17.

This snake had been kept without food for ten days.

This is one of the swiftest and strongest of all our North American Ophidians. I have seen it attack the Rattlesnake, and sever the head almost completely from the body. In its habits, food, and swift motions, it resembles very much the Coachwhip Snake (Psammophis flagelliformis).

9. Alligator Mississippiensis, Daudin (female). Alligator. April 30.

The blood was abstracted a short time after the animal was shot in a small stream. The reptile was remarkably fleshy, and the abdominal cavity, especially about

the kidneys, was lined with fat.

The blood was much more abundant than in a male Alligator, which was captured in the same locality in the month of March, and kept without food or drink for three weeks. It also did not coagulate so rapidly.

From the starved Alligator, not more than three fluidounces of blood, with care, could be collected, the veins and arteries of the neck having been opened whilst the animal was living. Although the subject of experiment had been shot for half an hour, still the blood flowed from the jugular veins and carotid arteries in rapid streams, and more than ten fluidounces were readily obtained.

The hole of this Alligator was in the bank of a small stream, which flowed through an extensive salt marsh, abounding with small Fishes and Crustaceans. This reptile, therefore, was abundantly supplied with food.

10. Chelonia caretta, Linnæus. Loggerhead Turtle. July 20.

The blood was examined two days after its capture. During this time, it was kept in a tub of salt water, and supplied with small Fishes.

The blood first drawn coagulated more slowly than that drawn last.

Portions of the blood were placed in several vessels and allowed to coagulate; and, in every instance, the blood-corpuscles settled to the bottom of the vessel, leaving above a transparent clot.

When first abstracted, it was of a dark red color, not so black as venous, but much darker than the arterial blood of warm-blooded animals. This is readily explained when we consider that the venous and arterial blood is mixed in the ventricle of the heart.

The reaction of the blood was slightly alkaline.

Whilst taking the specific gravity of the serum, which had been separated from

the clot for several hours, another small clot separated in the specific gravity bottle, having the characteristic appearance of fibrin.

The cavity of the abdomen contained half a fluidounce of clear serous fluid, which coagulated upon standing.

11. Chelonura serpentina, Linnæus (male). Snapping Turtle. July 16. The viscera of this Chelonian are represented in Fig. 8.

This reptile had been captured four days, during the greater portion of which time it was placed in water and supplied with Purslain (Portulacca oleracea).

The portions of blood drawn first coagulated more slowly than those drawn last. We have found this phenomenon to occur with all animals whose blood coagulated sufficiently slow to admit of a comparison of the times of coagulation. It appears to be an effort of nature to arrest hemorrhages. The manner in which the albumen of the blood is converted into fibrin is unknown. From the rapidity of the change during bleeding, it appears to have some connection with the nervous system. Whether it be due to nervous influence, or the action of the capillaries upon the albumen, or the mutual reactions between the corpuscular floating glands of the blood, remains to be demonstrated.

The coagulum was small and inconsistent.

The great majority of the blood-corpuscles settled to the bottom of the vessel, and were not included in the clot. In these respects, the blood of the Chelonura serpentina resembled that of Fishes and Frogs.

The serum was of a light yellow color, and, when treated with sulphuric acid. and gently heated, the characteristic musky odor of the animal was developed.

12. Emys Terrapin, Schoepff (female). Salt-water Terrapin. July 3. This terrapin had been captured twelve hours.

Specific gravity of its blood

serum

1035.3

1012.7

The serum was of a golden color, resembling that of the Emys serrata and Emys reticulata,

13. Emys reticulata, Bosc. Chicken Tortoise. June 6.

This Chelonian was captured in a pine-barren, and kept without food or drink for thirty-six hours.

The portions of blood first drawn coagulated more slowly than those last drawn. This is universally the case with the blood of cold-blooded animals.

The serum was of a bright orange color.

The alimentary canal was empty as far as the colon. The rectum and colon contained the claws and shells of small crustaceans, and the seeds of berries.

14. Emys serrata, Daudin (female). Yellow-bellied Terrapin. May 26. This terrapin was taken in a swamp and kept out of the water, without food, for three and a half days.

The first portion of blood drawn was placed in a small beaker glass, and coagulated so slowly that the blood-corpuscles sank to the bottom of the vessel, and a transparent clot floated above. This was not the case in the portions abstracted subsequently.

The serum was of a bright golden color, and, when kept for twelve hours, partially coagulated, resembling jelly.