48 BULLETIN 17 5, UNITED STATES NATIONAL MUSEUM 



two continuous black stripes are present on the anterior part of the 

 dorsum, which break up to form a series of paired elongated annuli, 

 which in turn become progressively less elongated posteriorly, until 

 they fuse in the midline to form a single series of ovoid annuli. In 

 deppei and jani, and m all other forms of the genus, continuous dorsal 

 stripes are lacking, and in all but lodingi, which has the dorsum uni- 

 formly black, and mugitus, which has the anterior spots indistinct or 

 lacking, the pattern consists of a series of large quadrangular, ovoid, 

 or saddle-shaped spots throughout the length of the dorsum. This 

 form, like the two subspecies of deppei, may be distinguished from all 

 other forms of the genus by the presence of two rather than four 

 prefrontals, and the entrance into the eye of two supralabials on each 

 side instead of one. 



Description. — Specimens of this form, in common with others of 

 the deppei group, are slenderer than the others of the genus. The head 

 is rather narrow, but the snout is blunt and almost square. In the 

 limited number of specimens available the tail forms from 0.122 to 

 0.138 of the total length, the average being 0.132. The largest 

 specimen examined measured 2,100 mm. in length. 



It is difficult to determine properly the scale characters of forms 

 that are known by only a few specimens, and although access has 

 been had to the collections of all the large and most of the small 

 museums in the United States, this form is represented by only four 

 specimens in the United States National Museum. On the basis of 

 these examples, the scutellation of the species may be described as 

 follows: Dorsal scale formula 27-27-21 in two specimens, 27-27-20 

 m a third, and 25-27-19 in the fourth; ventral scutes 236 to 249 (aver- 

 age 241.7); caudals 61 to 71 (average 66.7); supralabials 8 or 9/8, with 

 the fourth and fifth or the fifth and sixth entering the eye; infralabials 

 11 to 13, most frequently 12; preocular single; postoculars 2 or 3; 

 loreal present; azygos between frontal and prefrontals lacking; rostral 

 rather flattened and as broad as or broader than long; frontal un- 

 divided. 



The dentition is as follows: Mandibidar teeth 20 to 22, decreasmg 

 slightly in size posteriorly; maxillary teeth 18, decreasing slightly in 

 size posteriorly; palatines 9 to 12, subequal, slightly smaller than the 

 mandibular and maxillary teeth; pterygoids 15, smaller than the pala- 

 tines and decreasing slightly in size posteriorly. 



The pattern is the most remarkable in the genus and is unique in 

 having two continuous black stripes on the anterior part of the dor- 

 sum. These stripes extend from about one-fourth to one-third the 

 length of the body, are separated by 3 and 2 half scales, and vary 

 throughout their length from 1}^ to 3 and 2 half scales each in width. 

 Posteriorly the narrowing, which occurs at more or less regular 

 intervals, becomes more marked until the stripes break up into a 



