HERMAPHRODITISM. 69 



VI. Degrees of Normal Hermaphroditism. — From what 

 has been already said, it is evident that hermaphroditism may be 

 more or less intimate. As an entire plant, an Arum is hermaph- 

 rodite, with female flowers on the better nourished lower portion, 

 and male flowers above. This may be paralleled by the red coral, 

 which is sometimes female as regards one branch, and male as 

 regards another. If we keep, however, to hermaphrodite individuals, 

 it is evident that an orchid, with stamens and carpels united, is more 

 closely hermaphrodite than a buttercup flower. So in a leech, with 

 the ovaries far forward, and independent of the long row of testes, the 

 hermaphroditism is less intimate than in a tunicate, where the testes 

 and ovary may form one mass, the male cells spreading over the 

 surface of the ovary. In the same way, the organ of a scallop, 

 which exhibits more or less distinct male and female portions, is in 

 a state of less intimate anatomical hermaphroditism than the oyster, 

 where the same caeca of the same organ fulfill both functions at 

 different times. 



This last caution must be kept in view throughout. If the her- 

 maphroditism be very intimate, — that is, if the seats of the ovum- and 

 sperm-production be very close to one another, — it is not to be 

 expected that the development of the two kinds of cells will go on 

 simultaneously. Such would, indeed, be a physiological impossibility. 

 Antagonistic protoplasmic rhythms may rapidly alternate, but can not 

 coexist. Whether the hermaphroditism be anatomically intimate or 

 not, there is throughout, in varying degrees, a tendency to periodicity 

 in the production of male and female elements. Such a want of ' ' time- 

 keeping" between the sexes is called, in botanical language, dichog- 

 amy, and is one of the conditions which render self-fertilization rarely 

 possible. Both in plants and in animals, the male function has in the 

 majority of cases the precedence. Thus " protandrouo dichogamy" 

 (stamens taking the lead) is very much commoner than ' ' protogynous 

 dichogamy," where the carpels are first of all matured. This agrees 

 with the curious cases of Angiostomum and Cymothoidce already men- 

 tioned, where the organ was first male and then female, and indeed 

 with at least most cases among closely hermaphrodite animals. Where 

 the male organs are situated in one part of the body, and the female 

 organs in another, there is less reason against the production of 

 sperms going on at the same time as the production of ova. The 

 very physiological conditions which first determined the position of 

 the ovaries here and the testes there, may remain to render it possible 

 for the two opposing functions to go on at the same time. 



The common snail {Helix) is not only easily dissected, but in the 

 complexity of its arrangements is full of interest. Here not only are 



