576 John Beard 



lida the unisexual state occurs in nearly ali eases , including nearly ali 

 the lowest forms , and I thiuk we are now entitled to assume that the 

 more primitive and originai state in the genus Myzostoma is the uni- 

 sexual. 



And now we are in a position to trace out the development of, 

 and get some due to the meaning of hermaphroditism in the Myzo- 

 stomidae. 



It is obvious that the starting point of the series is the unisexual 

 form such as 31. inflator or M. Murrayi. The next stage in the pro- 

 cess is imperfect hermaphroditism with fully developed males. — A 

 hermaphroditism in which male organs are beginning to be developed 

 but are not yet functional. This is seen in M. cysticolum. The Euro- 

 pean M, glahrum gives us further development, there we have herma- 

 phrodites with both male and female organs fully developed and func- 

 tional , but stili with males, the males however only in small numbers, 

 and then only when perfect or imperfect hermaphrodites sit singly on 

 a Comatida^ the forms which possess no males living in groups of two, 

 three, or more, and probably reciprocally hermaphrodite. Lastly , we 

 probably possess in some of the remaining species of the genus perfect 

 hermaphrodites without males, the males having become extinct. This 

 is probably the case in M. cirriferum^ which usually forms a small co- 

 lony of several individuals on each Comatida mediterranea. 



So far as is known the remaining species of Myzostoma are her- 

 maphrodite and have no males. It must however be borne in mind 

 that males may and probably will be found in some cases at any rate. 



It may be useful and interesting to tabulate the results obtained in 

 the Girripedia and in Myzostoma. 



Cir ripe dia. 



Ibìa Cumingii unisexual, males possess stomach. 



Scalpellum ornatum unisexual, males without stomach. 



Scalpellum vulgare hermaphrodite with males , males with- 



oiit stomach and quite degenerate. 



rmaphr 

 My zostom idae. 



Ihìa qiiadrivalvis and most species of 

 Cirripedia hermaphrodite without males. 



31. inßata \ 



31. 3Iurraiji ] perfectly unisexual. 



31. ctjsticoluiìt unisexual with rudiments of hermaphro- 

 ditism. 



31. glabrura hermaphrodite with males. 

 3£. cirriferum and other species of 3Iy- 



zosfoma hermaphrodite without males. 



