l'J0(5.J AXATOMY i)F CEXTUUl'JIOIMTS CALCECS. 869 



ca'/tlcala, Galeiis canis, and nunierons other iSeliichiaii.s ; oii the 

 contrary, the two regions noi-mally included an angle of ttt least 

 120°. In C. squamidosus (and the same was the case in a sj)eci- 

 nien of C. gramdosus which I examined at the British Museum), 

 " the anterior [portion of the stomach] is much the larger, of an 

 elongate form, narrowed towai'ds its posterior extremity ; it 

 passes l)y an abrupt bend into the second reverted portion, which 

 is the narrowest part of the intestinal tract," ^^ and hence is quite 

 different from its supposed congener. 



Since it is impossible within the limits of the present paper to 

 give a comparative account of the anatomy of the gut of Selachians 

 or even Squalidie, I will content myself with merely further 

 remarking that the conditions both of the two portions of the 

 stomach of C calceus described above, and of most of the other 

 features of the gut about to be described, diffei' from those found 

 in all other Squalida^ — which is not at all remarkable considering 

 the extraordinary variety of form of the alimentaiy canal found 

 in this family. 



The pyloric poi-tion of the stonjach of fj. calceus ends in a very 

 short and small cul-de-sac, or, in other words, the duodenum 

 or homologue of the bursa Entiana arises from the side of the 

 pyloric region just before its termination (fig. 3). This duodenum 

 is remarkable in that (as also to some extent in Lcemaryus 

 borealis, L. 'rostratu.s,iMK. /'^pinax niger) it is extremely elongated 

 and slender in form, and not abbreviated and globular as in 

 C'entrojjhorus sqitci'mtolosus, C. gramdosus, Scyllimn canicida, and 

 indeed most Selachians. It forms, as shown in fig. 3, a long- 

 slender tube, about twice the length of the cardiac portion of the 

 stomach, and at most one-quarter of the diameter of the pyloric, 

 and with a very small lumen, which pursues a slightly cm-ved 

 course until it joins the large intestine containing the spiral valve 

 at a point situated considei'ably posterior to the stomach. In 

 C. sqitamidosios (and C gra'nulosus), on the other hand, " the 

 spiral valve commences on the level of the posterior extremity 

 of the stomach," " as in Scyllium canicida. The large intestine 

 in C. calceus is not very long, being about three-quarters the 

 length of the pyloric portion of the stomach and but slightly 

 exceeding it in diameter at its widest portion. The contained 

 spiral valve commences at the level of the posterior extremity of 

 the pancreatic lobe which is in contact with the large intestine 

 (shoi-tly to be desciibed), and consists of about seventeen oi- 

 eighteen spiral turns. Running parallel with the two portions 

 of the stomach and duodenum is an enormously elongated bile- 

 duct (associated with aiteries and veins for its entii'e length and 

 with the large hepatic-portal vein for the greater part), whicli 

 originates in connection with the right lobe of the liver and 

 terminates at the junction of the duodenum with the large spiral - 

 valve intestine, which it entei's by a conspicuous aperture on the 



11 Giiiither, ' Clialk'nger ' Koport on the Deop-Sea Fishes. 1887. 



