25-i Mr. J . BuUar on Ilermajyhroditism 



organs. Considering the larger dimensions attained by the 

 forms living in Avells^ it would seem that those of the lakes, 

 although inhabiting much larger pieces of water, arc in cir- 

 cumstances less favourable to their development, and are, in 

 a manner, atrophied." 



XXI. — Hennapliroditism among the Parasitic Isopoda. Bejyhj 

 to Mr. Moselerj^s Remarks on the Generative Organs of the 

 Parasitic Isojjoda, By J. BuLLAR, B.A., Trinity College, 

 Cambridge. 



'O" 



In the January number of this Journal Mr. Moseley attacks 

 some statements Avhich I had made in a paper on the Gene- 

 rative Organs of the Parasitic Isopoda (Journ. of Anat. and 

 riiys., Oct. 187G). He discredits ray discovery of hermaphro- 

 ditism in this group, and bases his arguments mainly on the 

 supposition that the organs which I have described as testes 

 are, in reality, spermatophores or parts of them. 



Before answering Mr. Moseley's objections, I may perhaps 

 be permitted to supplement my previous account of the anatomy 

 of the testes by some facts which, though they do not fully 

 elucidate the development of the spermatozoa, are, I trust, 

 amply sufficient to demonstrate the untenable nature of Mr. 

 Moseley's suggestions. 



The testes in these animals consist of three pear-shaped 

 bodies,each invested bya special membrane, which is constricted 

 to form a narrow neck before becoming continuous with the 

 wall of the ovary. In the case of Anilocra mediterranean the 

 narrow portion is elongated to form a short duct. Each of the 

 testes receives at its free end a special bundle of blood-vessels. 

 The testes usually contain numerous spermatozoa, which may 

 be seen passing down along the outer border of the ovary into 

 the vas deferens. In some cases, however, they contain few 

 or no spermatozoa, and are filled with a cellular blastema, from 

 which, doubtless, the spermatozoa are developed. 



The position of the testes is so invariable and their structure 

 so uniform, that it is incredible that, had Mr. Moseley seen my 

 preparations (which, I need hardly say, I should have been 

 only too delighted to have shown him, and thus have saved him 

 the trouble of writing his communication) and not merely the 

 drawings, he could have mistaken the testes for spermatophores. 



The vas deferens is a narrow duct lined by a flattened 

 epithelium ; at its lower extremity it presents an enlargement, 

 and opens into a distinct penis situated on the ventral wall of 

 the last thoracic segment. 



