570 John Beard 



butis hermaphrodite with fully developed and highly 

 organised males (fig. 30). 



In size 1j;iese males vary very much from Vio mm to about 1 mm in 

 length , which is about the maximum. I bave never found them larger 

 thau 1 mm, and two whicb I kept living on their host for over a month 

 died without increasing even in the least in size during that period. — 

 The hermaphrodite forms on which they sit always exceed them very 

 much in size. In most respects except in the total absence of ali 

 trace of female organs the males resemble in their anatomy the 

 hermaphrodites on which they sit. 



But in the males the nervous system seems to be richer in 

 ganglion cells than in the hermaphrodite. A definite body cavity also 

 seems to be present. It is small in size and lies above the alimentary 

 canal in the position of the so-called uterus of the hermaphrodite (fig. 

 35,37). In the males the male genital organs are well developed and 

 generally occupy a considerable portion of the body. In trans verse sec- 

 tion the testes are seen to fili up ali parts of the body not occupied by 

 muscles, alimentary canal and nervous system (figs. 37, 38). These 

 males usually sit on the extreme front of the dorsum of the hermaphro- 

 dite , and not as one might expect , and as indeed Semper stated, near 

 the female genital aperture. This position they probably take up in 

 order , while beiug in dose connection with the hermaphrodite , to get 

 more food ; for there they are nearer the mouth of the Comatula. This 

 explanation of their position is indeed the same as that given by Prof. 

 Geaff , but unlike bis explanation it is not given as the reason why 

 they sit on the hermaphrodite form. He thought they were young which 

 were either crowded out from the mouth region of their host or in the 

 cases when only one or two individuai M. glabrum were parasitic on 

 a Comatula^ which in leaving its free life had chanced to crawl up the 

 back of one of the individuals already there, and finding it could get 

 plenty of food there it remained. He pictured them with proboscis long 

 extended in order that they might get as much nutriment as possible. 

 But this figure! was probably taken from a specimen preserved in 

 alcohol. If so this sufficiently accounts for the extended proboscis, for 

 ali Myzostomidae killed in alcohol and seawater die with proboscis 

 extended. 



These males occur in nearly ali cases in which a large hermaphro- 

 dite M. glabrum occurs solitary on a Comatula. Rarely one finds a 



1 1. e. Piate I fig. 11. 



