416 SURGEON J, C. THOMrSON ON THE 



Anatomy. — There are two dental characters in this species that 

 are unparallelled among the Ophidia. The most striking is the 

 shape of the individual tooth, and the fact that the teeth borne 

 on the palatine bone are decidedly the largest. Each tooth is 

 set in the alveolar ridge with the anterior surface directed 

 forward and outward at an angle of 45° with the long axis of the 

 bone. When a tooth is viewed from the anterior surface, it 

 appears a trifle constricted at the middle ; towards the extremity 

 it flares out laterally, and terminates like a blunt spear-head, 

 with two cutting-edges that meet at a right angle. When 

 viewed from the side, this anterior cutting-edge is seen as a 

 narrow, beveled cusp, and from its base the tooth is continued 

 backwards as a hoiizontal process, the length of which is equal 

 to the broad diameter of the tooth. The edges of the cusp and 

 the tip of the backward — directed point are covered with brownish 

 enamel. 



The hypapophyses are present on the anterior vertebrae and 

 absent on the posterior. They have a moderately long base. 



In the writings of Cope * this form is credited with possessing 

 a coronoid bone. By Mr. Boulenger, however, it is placed in 

 the category of those in which this structure is absent. Two 

 specimens have been examined and no vestige of the bone can 

 be found. 



The external landmarks of the principal viscera in terms of 

 gastrosteges are as follows : — 



Total number of gastrosteges 177 1 00 p. cent. 



Apex of heart 52 29-4 



Liver, anterior tip 64 35-1 



,, posterior end 116 65-3 



Gall-bladder, middle 129 73 



Kidney, right, anterior tip 146 82-5 



,, ,, posterior end ... 155 



,, left, anterior tip ...... 150 85 



,, ,, posterior end ... 161 



Ileo-csecal valve 157 88"8 



The heart is large, and its position is indicated on the thoracic 

 walls by a distinct bulging. Over the base of the organ there 

 are two areas in which the scales are enlarged ; each area is 

 triangular, with the base along the edge of the ventrals and the 

 apex at the upper border of the fourth row. In the first row are 

 five scales, each of which is one-third larger than those before or 

 behind the heart. The scales in the seven dorsal rows are not 

 altered. The increase in the diameter of the body over the heart 

 is compensated for by an increase in the size of the scales in the 

 outer rows, and not by the interpolation of an additional series. 



The tracheal rings are complete from the glottis to the ninth 

 gastrostege. From this point the rings are interrupted, and the 



* Croc, Liz. & Sn. N. Amcv 900, p. 731. 



