1914.] NATURAL SCIENCES OF PHILADELPHIA. 291 



with a reduced scale count posteriorly. In each species this reduced 

 scale count is l^rought about by the loss of definite scale rows. The 

 discovery of this phenomenon was made by Mr. Ruthven while 

 studying the genus Thamnophis.^ 



Two additional characters bearing on this subject may be entered 

 into. If a series of one species is critically recorded, it will be found 

 that not onlj^ is there a definite sequence of suppression, but that a 

 given scale row terminates at about the same relative position on 

 the spinal colunm in each specimen. Also, that the suppression of 

 a scale row is in fairly definite relation to the posterior end of an 

 underlying organ. 



It is to be understood that these two characters are stated in 

 general terms. . Barring individual variation, for which no allowance 

 can be made, they will be found to hold with satisfactory constancy. 



Bibliography. — The original description of this species is contained 

 on page 71 of the Synopsin Reptilium by Laurenti, published in 1768. 

 In this work the serpent was named Anguis ruffa. Throughout 

 literature it has been referred to by the emended name of nifa. It 

 is probably only a question of time before some philologist will 

 insist that the current term be again emended and that the original 

 incongruous spelling be perpetuated. 

 Cylindrophis maculatus (Linnseus). 



Specimen. — California Acad. Sci., No. 16,890. Ceylon. 



Female; total length 330, tail 6.5 mm. 



Squamation. — The number of scale rows, the sequence in which 

 they are added or suppressed, and the gastrostege level at which 

 these changes occur may be thus presented: 



Neck: 

 19 rows, V row ends, right 10th, left 8th gastrostege, leaving: 



Body: 

 17 rows, IV row added, right 39th, left 49th gastrostege, making: 

 19 rows, IV row ends, right 182d, left 184th gastrostege, leaving: 

 17 rows, which are continued to the vent. 



Gastrosteges 194, in the middle of the Iwdy 3 mm. wide, adjacent 

 scale row 2.5 mm. ^vide; anal divided, urosteges 5, entire. Praefrontal 

 the largest shield; one small postocular; supralabials 6, the third 

 and the fourth entering the eye; infralabials 6; anterior geneials 

 large; one pair and two azygos gular shields. 



Anatomy. — The tracheal membrane is narrow and is not lined with 



» 1908, Bull. 61, U. S. National Museum. 

 20 



