1887.] PROF. T. J. PARKER ON CARCHARODON RONDELETII. 35 



dorsal lobe, and the spleen («/j/.) being an elongated lobulated organ 

 of deep red colour, attached all along the right border of the pyloric 

 division of the stomach and continued on to the dorsal aspect of the 

 cardiac division. 



5. The Heart. 



The heart is very large, having the following dimensions in speci- 

 men C. 



ceiitim. 



Greatest width of ventricle 19 



„ length (antero-posterior) 1.5 



„ ,, of conns arteriosus 10-5 



,, width of conns arteriosus ft 



,, ,, of auricle (moderately distended) .... 22 



Width of sinu-auricular aperture 9 



,, of auriculo-ventricular aperture 4'5 



Thickness of wall of ventricle (about) 3'5 



Its general structure is quite normal. Tlie sinu-auricular valves 

 are obliquely right and left ; the auriculo-ventricular valves obliquely 

 dorsal and ventral. The coronary veins open apparently by a single 

 very large aperture situated in the sinus venosus immediately caudad 

 and dorsad of the left flap of the sinu-auricular valve. 



The conus arteriosus (Plate VI. fig. \S, con. art.) has three longi- 

 tudinal rows, each of three valves, one row being dorsal, the others 

 ventro-lateral. The posterior valves {v^) are pocket-like and very 

 thick ; each is connected to the posterior face of the corresponding 

 middle valve (v^) by a strong chorda iendinea, which in the dorsal 

 valve takes the form of a vertical membrane attacbed to the wall of 

 the conus along its whole length, while in the ventro-lateral valves 

 it is free except at the ends. 



The middle valves (v^) are very small and thick, forming knobs 

 rather than pouches ; their anterior edges are connected to the walls 

 of the conus by several chordce tend'mece. The anterior valves (»^) 

 are pocket-like and are in close contact with one another at their 

 edges, whereas each of the middle and posterior valves is separated 

 from its fellow by a considerable interval. The edges of each of 

 the anterior valves are produced forwards, forming a firm attach- 

 ment, but they have no chordce tendinece. 



There are, as usual, too large coronary arteries placed right and 

 left of the conus. 



6. The Urinogenltal Organs. 

 The ovary was too much decomposed in specimen C for anything 

 to be made of it ; in D it was quite small, so that the specimen 

 must have been immature in spite of its size. The oviducts have 

 the usual character ; in D there was a considerable dilatation in the 

 position of the oviducal gland in one oviduct, but only a very 

 shght enlargement in the other. The oviducts open into the exter- 

 nal compartment of the cloaca by papillilbrm terminations (Plate VI. 

 fig. 1 7, ovd.ap.). 



