PLATE 58. 



Intestines of ANTACEA and CERATODUS. 



Fig. 1. Heptranchias PERLO. M. C. Z. 945 (Piige 21). Fig. 2. Cephaloscyllium umbratile. 

 M.C.Z. 1044(PagcSO). Fig. 3. Lsurus punctatus. M. C. Z. 1249 (Page 36). Fig. 4. Hemigaleus 

 pECTORALis. M. C. Z. 847 (Page 150). Fig. 5. Pristiopuorus japonicus. M. C. Z. 1045 (Page 

 246). Fig. 6. Ceratodu-s fosteri. M. C. Z. 9827. 



There are marked differences between the intestine of the Plagiostomia and that of Ceratodus. 

 Tlie stomach of tlie former is distinctly separated fi-om the spiral intestine, while that of the latter is a 

 continuation forward of the spiral itself. The stomach and intestine of Ceratodus, fig. 6, form a con- 

 tinuous spiral the characters of the inner surfaces of which change from the villous of the stomach proper 

 to the absobent of the intestine in a single turn of the winding course. The number of turns in Ceratodus 

 is nine or ten; the axis of the spiral is firm and muscular. The number of turns in the intestinal spiral of 

 the Plagiostomia varies in those dissected here from four in Hemigaleus, fig. 4, to thirty-nine in Isurus, 

 fig. 3. 



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