24 ZOOLOGY. 



Besides the reptiles above described there were also in the collection of Dr. Heermann two 

 specimens of Holbrookia maculata, which is said to be very abundant in Texas, being often found 

 in the holes of the prairie dog, (Arctomys ludovidana,) and a fine specimen of Ilerpetodryas 

 aestivus. This does not appear to differ essentially from the If. aestivus of Pennsylvania. It is 

 somewhat more robust, the scales are broader, and there are some unimportant differences in 

 regard to the smoothness of the external and inferior rows of scales, but these are not of suffi 

 cient importance to constitute specific characters. In the genus Herpetodryas , the opening of 

 the nostril is in a single plate, or between two plates according to Dumeril and Bibron. In 

 Leptophis always between two plates. The Col. vernalis of DeKay belongs to the genus Herpeto 

 dryas, and in our opinion should not be separated from it, because it has smooth scales, those of 

 aestivus being carinated. Examples of Leptophis may be found in Leptophis smaragdina, Lept. 

 lateralis, and Lept. leiocercus, the scales of the trunk of which are carinated, and those of the 

 tail smooth. Ten species of Leptophis are described by Dumeril and Bibron in their Erpetologie 

 Generale. 



There was also in the collection a full grown specimen of Rhinocheilus lecontii, Baird and 

 Girard, caught about one hundred miles from Pecos river, in the open prairie. It corresponds 

 very well with the description in their work on serpents, except tha tthe pre-abdominal scuta 

 is entire and not bifid, as they represent it, and that the sub-caudal scutellae are not all single, 

 nineteen of the latter being bifid. 



There is also a small plate behind the occipital, 190 abdominal scutae, 1 bifid pre-abdominal, 

 28 single sub-caudal towards the anus, then 4 rows of bifid, then 1 single, and lastly 15 bifid, 

 as in Coluber and Tropidonotus. 



Dimensions. Length of head five-eighths of an inch ; breadth | an inch ; length of body 16 inches ; of tail 3 inches. 



GEN. OBS. Future inquiries must determine whether Ehinocheilus lecontii should be removed 

 from the genus Rhinechis of Michaelles, of which but one species has heretofore been described, 

 viz : the Rhinechis scalaris, of which there is a good figure in Bonaparte s Fauna Italica. In 

 the genus Rhinechis, as characterized by its author, the plates under the tail are all bifid. 



Dimensions of the specimen of aestivus,* from Texas : Length of head six-eighths of an inch ; breadth three-eighths ; length 

 of body 1C^ inches ; of tail 10 inches ; circumference of body If inch. 



* Leptophis majalls, B. & G. Marcy s Report, pi. IX. 



