1915.] NATURAL SCIENCES OF PHILADELPHIA. 183 



River, in the moist situations of the wooded parts of the islands, if 

 not also in the dense cypress thickets. It is beautiful and is extremely 

 lithe of body. It frequents the edges of the little "houses" or islets 

 on the prairies, coursing among the water plants like a true water 

 snake. Of its expert swimming ability we had one fine illustration. 

 On the widest part of Billy's Lake we noticed a small snake several 

 rods ahead. It was halfway across in its course. We raced to head 

 it off, and swift and straight it did make its course. It had almost 

 reached the other shore when one of us hit at it, only to see it dive 

 deftly. It remained under water for a short time and soon re- 

 appeared on its back trail. We circled slowly towards it and when 

 near it stopped. It came immediately to the boat, apparently more 

 from curiosity than from exhaustion. This species must be accredited 

 with very good aquatic skill and endurance. 



Food. — Its food is mainly small aquatic animals. In one specimen 

 were insect remains. Frogs seem to be a prominent food with this 

 species. Four of the ten had eaten frogs, one having two southern 

 meadow frogs {Rana pipiens sphenocephala) in its stomach and 

 another had one of this same species. Another snake had captured 

 the cricket frog (Acris gryllus) and a fourth had eaten a pine-wood's 

 tree frog {Hyla femoralis), all these frogs except the last suggesting 

 an aquatic foraging ground for the species. Besides the frogs, there 

 were indications that they occasionally eat fish and other animals 

 of the water. 



Breeding. — Three specimens taken in the early part of July showed 

 the egg development to be not far advanced. One had 5 eggs, 

 another 8 and one 10. The number of young of this ovoviviparous 

 snake is comparatively few and must be born in late summer or early 

 fan. 



Parasites. — This species and its relative, T. sirtalis ordinatus, were 

 badly afflicted by internal parasites. In one specimen there were 

 parasites in the stomach, others partly in the abdominal cavity and 

 partly through the peritoneum and still others solely between the 

 peritoneum and the skin. In another specimen these occur in the 

 cephalic region and appear from the outside like large protuberances. 

 They lie just beneath the skin or imbedded in the muscles. 



17. Thamnophis sirtalis ordinatus (Linnseus): "Highland Moccasin"; Garter Snake; Com- 

 mon Garter Snake; Grass Snake; Little Green Grass Snake; Spotted Garter Snake. 



The garter snake is common in the swamp, and the local name, 

 "highland moccasin," indicates that the natives consider it more 

 upland and terrestrial than the Natrices or Thamnophis s. sackeni. 



