PAPERS OX BIOLOGY AND AGRICULTURE 127 



limiting it in this region. It is connected with the cupola 

 by a eylindrically shaped rod which bends medially and 

 laterally, forming an obtuse angle, and uniting with the 

 ventral margin of the cupola at its junction with the 

 corau trabeculae (Figs. 7, 9). 



The ventral half of the planum lateralis, just before it 

 bends to form the anterior vertical plate, is pierced by a 

 long slit-like foramen which appears to be unrelated to 

 any nervous structure and may represent merely an in- 

 complete chondrification here (Figs. 7, 9). On the pos- 

 terior median surface of this vertical plate is an S-like 

 formation which has just started to form in the younger 

 stage (Figs. 6, 12). This structure is continuous with the 

 planum lateralis. In the older stage a rod-shaped 

 cartilage bar extends from the upper portion of it pos- 

 teriorly at an angle of 45 degrees to the median line of 

 the skull (Fig. 9). This is unquestionably a nasal con- 

 cha, and is evidently homologous to that concha shown 

 by Gaupp (1900) in his description of the skull of the 

 lizard. 



This description of the development of the nasal cap- 

 sule of the snake is of considerable interest in itself; but 

 its greater interest lies in the comparisons that exist 

 between it and the other capsules of the reptilian class 

 as well as capsules among the amphibia. In following 

 Kunkel in his description of Emys, it appears that con- 

 siderable identity of structure exists in the ethmoidal 

 regions. The chondrocranium of the turtle is apparently 

 more compact than that of the snake, although homolo- 

 gous regions may be identified readily. Furthermore, 

 it would appear that considerable similarity exists be- 

 tween the capsules of certain urodeles and this capsule 

 of Xatrix cyelopion. To attempt to establish any basis 

 of phylogenetic continuity upon such a resemblance 

 would be unscientific ; and yet one cannot fail to note this 

 relationship. In both, the roof of the capsule is pierced 

 by a large rhonmboidal fenestra which appears to be 

 bounded by homologous regions. Similar capsules cap 

 the anterior end of each organ, and similar internasal 

 spaces separate the two. 



