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



end of which passes backwards into the fissure and commiinicates 

 with the oviduct, the other enters the apex of a conical projection, 

 fig. 1 a, which it will be seen is the retracted male intromittent 

 organ. 



Having given the above general notice of the parts as they are 

 seen on being laid bare, and partially drawn asunder, we now 

 proceed to a more particular description of the same after they 

 have been carefully dissected, premising that the description, as 

 well as the general notice, is taken from E. papillosa, except where 

 it is otherwise expressed. 



1st. Male apparatus : we have already said, that of the external 

 orifices, the male, fig. 2 a', lies in front of the other two. When 

 this orifice is laid open in a specimen that has the parts fully 

 retracted into the body, we find a short canal opening almost 

 immediately into a pretty large sac, fig. 7 a, which is nearly filled 

 by a somewhat egg-shaped body c, projecting into its interior. 

 The sac at its innermost end is found to be reflected upon the 

 exterior of the contained body, forming a coating for it. \^Tien 

 this body is examined by section it displays in its interior a fine 

 tube which is continuous with the testicular convolutions, d, at 

 the internal extremity, and at the other opens near the apex, e, of 

 the egg-shaped body above mentioned. This body is formed then 

 of a reduplication of the wall of the sac that opens at the external 

 orifice, and contains the termination of the testis towards the ex- 

 terior. It is capable of being elongated, drawn out to a point, and 

 protruded altogether from the sac that contains it, and the sac 

 itself is also capable of being everted through the external orifice. 

 The contracted egg-shaped body, and the sac in which it lies, on 

 being thrust out externally, assume the form of a much-elongated 

 and finely tapering penis, fig. 5 a, inclosing the excretory duct of 

 the testis which opens at its apex. When the parts are contracted, 

 this penis forms the internal conical projection alluded to at the 

 end of the general description. 



The testis, fig. 1 c. This is a tolerably large tube, intricately 

 convoluted in a somewhat zigzag manner, its coils bound together 

 by a tissue of delicate filaments, and by the branches of the ar- 

 tery and nerve distributed to them, into a pretty compact mass, 

 which lies in front of and upon the mucus-gland, and against the 

 light side of the buccal mass, partly concealing the penis. Wlien 

 the coils are all unravelled we have a tube of uniform diameter, 

 the length of which in one specimen was two inches, being greater 

 than that of the animal itself. It is of a pale flesh colour and 

 opake ; and if a portion be removed and examined in the com- 

 pressorium of the microscope, its walls are seen to be made up of 

 three concentric coats; the two outer are muscular, and their 

 fibres are longitudinal and transverse ; the innermost is a secre- 



