1906.] ANATOMY OF THE OPHIDIA. 33 



stomach is, as already mentioned, traversed by three thick folds, 

 which show here and there an interesting trace of a reticular 

 arrano-ement. There are occasional short branches of the folds, 

 which, although they do not reach another fold, indicate an 

 approach towards, or a reminiscence of, a reticular arrangement. 

 Towards the posterior end of the anterior part of the stomach the 

 folds lose their importance and smaller folds between them 

 appear. But the whole series of folds dies out upon a cushion- 

 like elevation. Then follows the shorter posterior region of the 

 stomach, which is entirely free from rugse of any kind. The 

 small intestine is short as compared with that of some other 

 serpents. Not counting its windings, it measures in a straight 

 Hne from the end of the stomach to the beginning of the large 

 intestine 51 mm., or 2 inches. About half of this consists of a 

 closely-folded section, which commences immediately after the 

 circular valve separating the stomach from the intestine. Then 

 follows a straight section, which just before its opening into the 

 dilated commencement of the large intestine bends once or twice 

 abruptly upon itself, thus constituting another shorter coiled 

 region. The intestine is lined with fine wavy folds. The large 

 intestine is also 51 mm. in length to the anus. 



Vascular Sijstem.— Though it is impossible to elucidate the 

 arrangement of the vascular trunks in a spirit-preserved specimen 

 in a thorough fashion, I have nevertheless been able to ascertain 

 certain facts which are of importance from a systematic point of 

 view. I have been able to follow the abdominal branches of the 

 aorta, and find that the first hepatic branches are disposed as 

 follows: — Thejirst branch which arises supplies the stomach, and 

 reaches that organ at about its middle. On a level with the gall- 

 bladder a second eqiudly stout branch is given off which divides 

 into two trunks : one of these runs forward and is gastric ; the 

 other has a posterior course and is intestinal. The next branch 

 of the aorta is that of the right testis ; it is of course very slender. 

 I did not discover the corresponding branch to the other testis. 

 The next artery to arise is the right renal, which enters the 

 kidney near to its anterior end. A rectal artery comes next and 

 is followed by the left renal, which is also the only artery of this 

 kidney and enters it near to its anterior end. Then follow three 



rectal arteries. 



Intercostal Arteries.— In the arrangement of these arteries 

 Ilysia plainly shows its affinities to the Boidte. In the last- 

 mentioned family * the intercostal arteries are paired structures, 

 which is not the case with, at any rate, many Colubridfe and 

 Viperid^e. In Ilysia the same paired structure is plainly visible; 

 furthermore, it is to be noted that the intercostal arteries are 

 reo-ular in their arrangement— that is, that they supply the inter- 

 costal spaces continuously, a pair of arteries corresponding to 

 each vertebra. This is, of course, also a Boine character. It is 



* Jacquart, Ann. Sci. Nat. (4) iv.; and Beddard, P. Z. S. 1904, vol. i. p. 338, & 

 P. Z. S. 1904, vol. ii. p. 108. 



Proc. Zool. Soc— 1906, Vol. I. No. III. 3 



