The Anatomy of Chlamydoselachus 



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about 55 mm. wide where it joins the pharynx, but it narrows rapidly to an almost uniform 

 width of 30 mm. throughout most of its length. The diameter of the widest portion of 

 the cardiac stomach is about 45 mm. 



In all the specimens in the American Museum, 

 a previous dissection had shown the stomachs to be 

 practically empty. Nevertheless in specimen No. Ill 

 the cardiac stomach had evidently been hardened 

 while in a distended condition, since its lumen is un' 

 usually large and its walls are very thin. In this 

 specimen, throughout a large portion of what is 

 presumably cardiac stomach, the wall is only about 

 1 mm. thick; I suspect, however, that most of the 

 mucosa is missing. The inner surface is smooth. In 

 my other specimens the cardiac stomach is less dis' 

 tended and its wall is appreciably thicker; the inner 

 surface is cast into slight longitudinal folds. In all 

 three specimens the thickness of the wall of the car' 

 diac stomach increases toward its caudal end, but 

 it is nowhere more than 2 or 3 mm. thick. 



On the right side near the caudal end of the 

 cardiac stomach of Chlamydoselachus, HdLwkts (1907) 

 describes and figures (my Text'figure 73) a more dc' 

 cided thickening (L.T.S.) which she suggests may 

 be a "lymphatic gland." Hawkes does not tell how 

 many specimens she studied, nor whether this thick' 

 ening occurred in more than one specimen. I have 

 found no such structure in any of my three speci' 

 mens. From specimens I and III, I have excised 

 some segments of the slightly thickened wall near 

 the caudal end of the cardiac stomach, and upon 

 microscopical examination have found only the layers 

 characteristic of a stomach, including an inner 

 glandular layer in a poor state of preservation. 

 CoUett (1897) states that in his specimen of 

 Chlamydoselachus measuring 1910 mm., the stom- 

 ach proper is small and proportionally narrow; its length is 340 mm., its breadth is 

 about 45 mm. 



In Heptanchus (Daniel, 1934) the stomach is U'shaped or V'shaped, the larger left 

 limb being the cardiac portion, and the smaller right limb, the pyloric division. In two 

 of my specimens of Chlamydoselachus a small division, the pyloric vestibule, is inter' 



Text-figure 73. 

 Digestive tube of Chlamydoselachus, 

 from the middle of the stomach to the 



middle of the valvular intestine. 

 B.D., bile duct; B.D.B.E., dotted line showing the 

 position of the enlarged end of the bile duct in 

 the wall of the bursa entiana; B.E., bursa entiana; 

 C, caecum at the hinder end of the larger arm 

 of the stomach; L.T.S. , thickening of the stomach 

 wall, probably due to a lymph node; Py.V., 

 pyloric valve; S., stomach; S.l. short arm of 

 stomach; S.V., spiral valve. 

 After Hawkes, 1907, first text-figure. 



