1906.] 



RESPIRATORY SYSTEMS IN THE OPHIDIA, 523 



Coluber catenifer agrees in most respects with Coluber onelano- 

 leucus, and tliese species, together with two or three others, have 

 been placed in a genus apart, viz. ^Fiti/ojyhis. The trachea in the 

 same way extends a long way down the lung, further, indeed, than 

 in Coluber melanoleucus. I traced the tracheal gutter some way 

 behind the liver, in fact to a point about two inches behind that 

 organ and close to the gall-bladder. In this region of the body 

 the lung has ceased to be vascular. As in the last species, the 

 lung-tissue is sharply marked olFanteriorly and there is an anterior 

 diverticulum of the lung, l^or could I find the oi'ifice of a second 

 lung. Transverse sections of the lung in the vascultir part of that 

 organ showed precisely the same features as have been indicated in 

 describing Coluber 'melanoleucus. The structure of the trachea 

 and lung, in fact, of the present species shows a slightly exaggerated 

 replica of the structure of the same parts in Coluber melanoleucus. 



Coluber catenifer var. sayi. — I have examined a snake which 

 is thus labelled, but I am not aware by whom it was identified. 

 It forms part of a small collection of Snakes in spirit belonging to 

 the Society. In Boulenger's ' Catalogue of Snakes in the British 

 Museum,' " Coluber catenifer var. sayi " is placed under Coluber 

 onelanoleitctos, which is distinguished from C. catenifer. In the 

 example referred to here, I find absolutely no difference from the 

 lungs of Coluber catenifer as described above. So alike are they 

 that I find no occasion for a description t. 



* Of the 45 species of Coluber described bj-- Boulenger (Catalogue of Snakes in 

 the British Museum, vol. ii. ISOi, pp. 29 et seq.) the two above mentioned are the 

 only species in which only one labial scale forms a part of the margin of the ej'e and 

 there are two suboculars. In four other species which have been assigned to the 

 genus Pityopliis both of these characters do not occur. The presence of a subocular 

 segmented otf from the preocular is common and occurs, I maj' take this opportunitj^ 

 of remarking, in an example of Coluber longissimus which I have examined, on one 

 side of the head with indications of approaching separation on the other. This point 

 is not mentioned by Boulenger in his definition of the species and is therefore, I 

 presume, not usual. I am able therefore here to correlate a peculiaritj' of internal 

 structure with an external modification, viz. in the scaling of the head. But without 

 a more exhaustive survey of the structure of the species of Coluber, it would be 

 unwise to attempt generic rearrangements. 



t It is clear therefore that the question of the species requires some consideration . 

 I extract from Boulenger's description in the Catalogue (p. 68; the following features 

 as distinctive of the two, viz. : — 



C. catenifer. Rostral as broad as deep or slightly deeper. Anterior chin-shields 

 longer than the posterior. Subcaudal scales more than 65. 



C. melanoleucus. Rostral much deeper than broad. Parietals usually broken up 

 behind. Anterior chin-shields much longer than the posterior. Subcaudals 

 less than 65. Some or all of labials with black sutures. 



The other characters used either overlap or are not diagnostic so far as these two 

 species are concerned. 



In one specimen of C. catenifer and two of C. melanoleucus belonging to the Society 

 I distinguish the above-mentioned characters with the exception of the black edo-es 

 of the labial, which occur in both species. In the latter the subcaudal scales were 

 48 and 57 pairs respectively ; in the single specimen of C. catenifer 71 pairs. In 

 this specimen, the prefrontals were not broken up, as is the case, according to Cope 

 (P. U. S. Nat. Mus. 1892), with C. wHJcesii ; there was a subocular below the preocular 

 and one subocular below the two postoculars. In the two specimens of C. melano- 

 leucus there was no subocular in front and one below the two postoculars. In all 

 other respects, save colour, these several individuals agreed with Boulenger's 

 description. Yet Baird & Girard (Cat. N. Amer. Reptiles in Mus. Smiths. Inst. 



