52 NOTES ON THE ANATOMY OF DINOPHILUS. 



this suggestion witli all reserve, it is perhaps possible* that in the 

 connective-tissue lacunae of the body of Dinophilus we have the 

 representative of the so-called "primary body-cavity/' whilst in the 

 fully developed male (fig. 13) the "secondary body-cavity" is 

 represented by the cavity of the testis, with which the funnels of 

 the vesiculse seminales are connected. 



B. Female. — The generative organs in the female D. . tseniatus 

 differ considerably from those of other known species of the genus, 

 in the fact that the ovaries are four-lobed. The general arrange- 

 ment of the ovaries will be understood by referring to fig. 2, where 

 it will be seen that the ovaries, like the testes, are paired bodies, 

 but that each half is subdivided into two lobes. Each lobe consists 

 partly of small primordial ova and (in a moderately mature condition) 

 partly of larger eggs which have already acquired the orange colour 

 which characterises the ripe eggs. The ovaries are covered by a 

 cellular investment, which is readily seen in fresh specimens to be 

 continuous from lobe to lobe on each side of the body. The ovaries, 

 as in D. gigas, are found on the ventral side of the stomach. No 

 ducts could be discovered in the living animal. Spermatozoa, 

 received during the process of copulation, occurred in almost every 

 individual in which the ovaries were at this stage or more highly 

 developed. In specimens in which the ova had become still further 

 developed, the eggs were no longer confined to the four ovaries. 

 As many as fourteen large spherical eggs of a distinct orange 

 colour may, in such cases, occur on the ventral side of the stomach 

 or intestine, and the two ovarian lobes of each side are then usually 

 pushed apart from one another by the occurrence of ripe eggs 

 between them. 



Fig. 14 represents a transverse section through the region between 

 the anterior and posterior ovaries of a female with numerous and 

 fully developed ova. On the ventral side of the stomach is a large 

 space, containing a great mass of ripe spermatozoa, which appears 

 to have no proper wall on its dorsal side at least, being in this 

 region merely roofed in by the stomach. Laterally its walls are 

 formed by the cellular investment of the ovaries, this investment 

 passing across the middle line of the body on the ventral side of 

 the space. In a section which passed through one of the ovaries 

 on each side, the ovarian lobes would simply take the place of the 

 ripe eggs shown in fig. 14. The cellular investment of the ovaries 

 already noticed in fig. 2 would be seen to surround each lobe com- 

 pletely, and to be further continuous across the middle line on the 

 ventral side of the int.erovarian space, exactly as in fig. 14. 



Fig. 12 represents a longitudinal section through the two ovaries 



* At has previously been suggested, for other animals, by the Hertwigs, 



