152 Trans. Acad. Sci. of St. Louis. 



terspaces of about three scales. The median line for about a width of 

 four scales is not spotted, or is very imperfectly so, forming a broad 

 vertebral band of a color much darker than the general ground. The 

 head is uniform brown; the lower part of the superior labial plates 

 only being yellow. On the yellow ground of the inferior surfaces there 

 appear, on the anterior third only, dark shades on the ventrals. These 

 extend and blend so that on the posterior two-thirds of the body-length 

 the color may be said to be bluish-brown, with yellowish subtriangular 

 yellow spots pointing forward. (Cope.) 



Size. — Length from point of head to vent 545 mm.; tail 180 mm. To- 

 tal length 725 mm. Adult male. 



Habitat. — Florida, Louisiana, Arkansas, Southern Illi- 

 nois, and Missouri. Missouri localities : Poplar Bluff, 

 Butler Co., and St. Francis Biver, Dunklin Co. 



Habits. — My son shot a few specimens of this snake at 

 Grinnell Lake, near Poplar Bluff, and I caught a few at 

 the St. Francis River, near Bertig, Arkansas. They were 

 sunning themselves on the moss, Ceratophyllum emersxnn, 

 and other water plants. When disturbed they slid down 

 into deep water — 6 to 10 feet. July 3, 1904, I shot a 

 female basking in the sun on water plants. I hit it in the 

 eye, which only stunned it long enough for me to catch it. 

 I kept it in captivity until September 20th, when it bore 

 nineteen live snakes, 265 mm. long. I found this species 

 quite common on the lower St. Francis River about Au- 

 gust 20th. 



Dates of capture.— May 19, 22; July 3; Aug. 20; Oct. 3. 



45. Nateix ehombifeea Hallowell. Diamond-backed Wa- 

 ter Snake. Holbrook's Water Snake. 



Tropidonotus rhombifer, Tropidonotus sipcdon var. rhombifer, Tropido- 

 notus fasciatus var. rhombifer, Nerodia holbrookii, Ncrodia sipedon 

 var. rhombifer, Nerodia rhombifer. 



Description. — Head narrow. Rostral broader than deep, visible from 

 above. Internasals much narrowed in front, as long as broad, or a lit- 

 tle longer, as long as or shorter than the prefrontals. Frontal one and 

 two-thirds to twice as long as broad, as long as its distance from the 

 end of the snout, shorter than the parietals. Loral as long as deep or 

 deeper. One anteorbital and three postorbitals, the lowest nearly meet- 



