SHAPE AND STRUCTURE OF ALIMENTARY VISCERA OF PORPOISE. 327 



These two projections coincided with the hollowed-out bases of the lungs, while 

 the heart occujjied the mesial depression, the diaphragm intervening in both cases. 



There was no gall-bladder, and therefore no quadrate lobe to the liver, but indica- 

 tions of a spigelian and a caudate lobe have already been noted. 



The microscopic structure of the liver, spleen, and pancreas did not materially differ 

 from the appearances of those organs in man. The sections of the pancreas displayed 

 the characteristic cells associated with acini and ducts. 



From an examination of the sections, we are inclined to think that the cells described 

 as "central acinar cells" are merely sectional views of the cells which line the com- 

 mencement of ducts that chance to lie upon the side of the section next to the observer ; 

 and further, that the so-called paranucleus or "nebenkern" results from the same struc- 

 tures lying on the side farthest from the observer, and therefore less distinct. Otherwise 

 it seems that in such clear and distinct sections these special structures should appear 

 more frequently than they do. 



It ought to be recorded that the tape-worm — Bothriocephalus latus — was found in 

 the intestine. This parasite has not hitherto been observed in the alimentary canal of 

 a marine mammal. 



Conclusions. 



(1) Although the porpoise, like other cetacea, is a mammal without hind limbs, 

 and although its innominate bones are reduced to a couple of slender rods, yet, in 

 the peritoneal arrangements associated with the posterior end of the abdominal 

 cavity, there is evidence of a pelvic cavity which has not hitherto been recognised as 

 such. 



(2) From the present observations, we agree with those previous observers who 

 have described the stomach of the porpoise as four-chambered, and we are in harmony 

 with them as regards the homologies of the first and second compartments, although 

 we regard the first compartment as developed from the primitive stomach, and not as a 

 dilatation of the post-diaphragmatic oesophagus. 



(3) We do not regard the " canal " or mural " passage," which lead onwards through 

 the wall of the second compartment, as the third compartment, but look upon this 

 " canal " as the inevitable association of the thick wall of the second compartment. 

 Moreover, it is not quite so long as the " passage " of communication between the first 

 and second chambers, and but little longer than the pyloric "passage," neither of which 

 have ever been regarded as homologous with separate compartments. 



(4) We find the third compartment in a distinct chamber beyond the wall of the 

 second, and clearly demarcated from the fourth, both by its somewhat spherical shape 

 and by its constricted outlet. 



(5) Although Jungklaus and other writers support the view that the third com- 

 partment of the adult porpoise is the mural " canal " or " passage " already referred to, 



