316 THE ZOOLOGIST. 



the active centres, as the latter in the least disturbed nooks contribute 

 to the formation of fibrin." 



" Sex in Crustacea, with Special Reference to the Origin and Nature 

 of Hermaphroditism, " was discussed by Mr. Geoffrey Smith. We can 

 only refer to his statement of the phenomena : — " The great majority 

 of Crustacea have the sexes separate, and this is also true of the phylum 

 Arthropoda as a whole. There are, however, two large groups of 

 Crustacea, the Cirripedia and the parasitic Isopoda, which are for the 

 most part hermaphrodite ; and since these two isolated groups stand 

 alone in this respect among allied groups, we may be certain that the 

 hermaphroditism has been secondarily acquired from some dioecious 

 ancestor. It is therefore interesting to inquire under what conditions 

 hermaphroditism may arise in a dioecious species. 



" The most searching analysis of hermaphroditism is afforded by 

 the phenomena of parasitic castration, which was first discovered by 

 Giard, and has been subsequently studied by the author and Potts. 

 The result of these studies has been to show that a number of animals 

 belonging to widely diversified phyla, but especially the Crustacea, 

 when attacked by various parasites, undergo an alteration in their 

 sexual nature of such a kind that at first the gonad in both sexes de- 

 generates to a greater or less extent ; secondly, the males assume in 

 varying degrees the secondary sexual characters proper to the female, 

 while the female, without assuming any male character, suffers a 

 certain amount of degeneration in the secondary characters proper to 

 the female. Finally, either on recovery from the parasite or else 

 during the degenerative process, the male may develop ova in its 

 testes, and these ova may grow to a very large size, lying side by side 

 with mature spermatozoa. The females, on the other hand, just as 

 they never develop male secondary characters, also never produce 

 spermatozoa in their ovaries. These results apply especially to the 

 effects of the Rhizocephala upon the Crabs which they infect. 



" We see then, first, that hermaphroditism in the Crustacea can be 

 called forth in its completion by an external cause acting upon a 

 sexually differentiated animal, and, secondly, that it can only be called 

 forth in this way in the male sex, not in the female." 



Mr. Oswald H. Latter, in his paper on " The Teaching of Biology 

 in Schools," dealt with a subject which shows how far school authorities, 

 as a rule, are still from a sound appreciation of biology and its methods : 

 — " Lastly, a word of defence against certain opponents is necessary. 

 It is by some maintained that anatomy and physiology are 'nasty,' and 

 even indecent, and not fit subjects of education virginibw puerisque. 



