Messrs. Hancock and Embleton on the Anatomy of Eolis. 91 



ting membrane, and is lined by numerous corpuscles similar to 

 those in the expressed contents of the tube. 



The contents of the tube are easily pressed out, and consist of 

 a tenacious mucus-like matter that contains a great number of 

 corpuscles of different size and appearance, fig. 9. These are 

 chiefly delicate transparent cells, some of considerable diameter, 

 perfectly circular and having a double outline. They are of three 

 kinds : 1st, those which are devoid of contents and of nucleus, 

 fig. 9 a ; 2ndly, those which present a large granular nucleus, 

 which is either within and lying close upon the wall, or projecting 

 about half their diameter beyond it, b ; and 3rdly, those which 

 are more or less completely filled with circular, granular and 

 unnucleated corpuscles, c ; these corpuscles are also seen in con- 

 siderable numbers, d, free, of various sizes and apparently under- 

 going development into cells. 



Spermatozoa have been observed among the contents of the 

 testis of E. coronata, though we have not been able to detect any 

 relation between them and the nucleated cells above described. 



The tube of the testis after the unravelling of its coils can be 

 traced a short way backwards, along the fissure between the lobes 

 of the mucus-gland, where, after undergoing a sudden and re- 

 markable constriction, it opens into the oviduct where that tube 

 is abi'uptly bent upon itself, figs. \h2k. 



The penis of E. coronata when exserted dificrs from the elon- 

 gated conical organ of E. papillosa in being much bulkier in pro- 

 portion to the size of the animal, and in its extremity being much 

 enlarged and terminated by an almost circular fungiform mem- 

 branous expansion, near the anterior border of which the excre- 

 tory duct of the testis opens. This peculiarity appears to be ac- 

 counted for by the modified form of the duct leading to the sper- 

 matheca in this species, and will be again noticed further on. The 

 testis, fig. 3 c, differs also from that of E. papillosa in being very 

 short, but of much greater diameter. The constriction at the 

 part where it joins the oviduct is more strongly marked, and pro- 

 longed like a small duct. Fig. 8 represents the penis of E. co- 

 ronata retracted within its sheath in the interior of the body. 



The penis of E. Drummondi, fig. 6 a, is similar to that of E. 

 coronata, and is given from a specimen preserved in spirits, in 

 which it was exserted. The testis, fig. 4 c, is somewhat shorter and 

 thicker. 



The male organs of E. olivacea resemble those of E. coronata. 



2nd. Female organs : the position and general appearance of 

 the ovary, fig. 1 d, have already been described. On further ex- 

 amination the organ is found to be intersected by a longitudinal 

 median fissure, which can be traced deeply into its substance, 

 and which divides it into two principal lateral masses ; smaller 



