144 Transactions of the 



to the dorsal surface of the anterior part of the mantle ; in several 

 cases it was met with lying detached by the side of the animal, 

 having been broken off by the covering glass ; in one case (Fig. 2) 

 it looked as if it were situated within the pharynx, it having been 

 twisted round, and so placed as to be seen through the parietes of 

 the body. 



In several cases bundles of smooth muscular fibres were visible 

 which seemed to run from the walls of the anterior part of the 

 body to be inserted into the commencement of the neck. 



A spherical body resembling a mulberry in shape is situated at 

 the posterior end of the animal behind the intestine ; it appeared to 

 be composed of rather large cells, each containing a nucleus ; this 

 could be nothing else than the ovary. Gegenbaur saw this body, 

 and mentions that in one specimen it contained a large ovum in the 

 centre, but in my specimen no other contents than the above-men- 

 tioned cells were visible. In many specimens there was an elongated 

 granular body in close juxtaposition to the posterior side of this 

 ovary. I had no opportunity of observing into what structures 

 these granules were developed, but Gregenbaur has described in 

 A. furcata and A. acrocerca an organ occupying the same position, 

 which he says contained zoosperms at one period of its existence. 



A pair of curious bodies are situated in an elevation of the 

 diaphanous mantle behind the anus on each side of the body ; they 

 seem to be composed of carbonate of Hme, but their use is by no 

 means apparent. In some specimens they resemble an acorn in 

 shape, in others they are simply oval. 



With regard to the organs of circulation, Gegenbaur mentions 

 that the heart is the easiest of all the organs to be seen ; it appears 

 strange, therefore, that tliis viscus should have entirely escaped me. 

 The only appearance which could be interpreted as having anything 

 to do with that organ occurred unfortunately in the last specimen 

 that came through my hands, so that I was unable to come to any 

 definite conclusion about it. The appearance consisted of several 

 curved rods, which seemed to embrace about half the circumference 

 of the stomach, and to pulsate with great rapidity and regularity in 

 a fore-and-aft direction. These curved rods might vrell have been 

 the optical expression of folds in the transparent walls of the organ 

 in question, and as the specimens I am describing undoubtedly 

 belong to a species distinct from either of those discovered by 

 Gegenbaur, it might happen that the heart would occupy a different 

 position. 



The appendage differs from that structure in both A. furcata 

 and A. acrocerca in shape and mode of attachment to the body. 

 At the free extremity it is bifid, as in the former species ; at the 

 proximal end it has the same form, as in the latter species. The 

 central axis forms the only means whereby it is united to the body. 



