54 ORIGINAL ARTICLES. 



small worm was a different species, we ought to see in it eggs in course 

 of development, which, however, I have never found to be the case. 



The extraordinary disproportion in size between the sexes, though an 

 extreme case, is not entirely without analogy in the animal kingdom. 

 Nordmann first (" Micrographische Beitrage," Pt. 2 — see also Huxley's 

 Lectures, " Medical Times and Gazette," August 22nd, 1857, p. 187), 

 discovered that in certain Crustacea the males are much smaller than the 

 females. This is the case, principally, in the genera Actheres, Brachiella, 

 Chondracanthus, and Anchorella, in which the minute male may gene- 

 rally be found attached to the female in the neighbourhood of the vulva. 

 The minute and " complemental" males, discovered by Mr. Darwin in 

 the genera Scalpellum and Ibla, afford .cases in point from among the 

 Cirripedia- 



In spite, however, of analogies pointing in the same direction, one 

 cannot but be astounded at the existence of a species in which, as in the 

 present, the male is more than twenty-eight thousand times smaller than 

 the female, which, if we may so say, helongs to, it. 



I was not able very satisfactorily to ascertain the manner in which 

 the two are fastened together; but it seemed as if the large worm had a 

 small sac-like depression of the skin, PI. 1 , /. 14, into which a correspond- 

 ing projection of the small one closely fitted. The inner contents of the 

 body passed into the projection, but I could not perceive any penis or 

 spermatozoa, nor was the ovary of the female connected with the place 

 of attachment. The two creatures adhere together more closely than this 

 condition, taken by itself, could account for ; and, as in the somewhat 

 similar case of Syngamus the union is effected by the presence of a sort 

 of cement, it was natural to suppose that the same might be the case 

 here. Neither Mr. Busk, however, who was kind enough to look at 

 the junction, nor I, could see any trace of cement; and it is evident, 

 therefore, that if the two skins are not continuous, they are, at least, per- 

 haps by long contact, very closely united to one another. 



Considering all these facts, there seems every probability that in 

 this little creature we have the male Sphserularia ; but until the Sper- 

 matozoa and the transformations are known to us, the fact cannot be re- 

 garded as being conclusively established. 



It only remains for us to consider the natural position and affinities 

 of Sphaerularia, though it will not be possible to come to any satisfactory 

 conclusion until we know more of the anatomy and development of the 

 young. It is, of course, evident that Leon Dufour was right in placing 

 it among the Nematodes ; but when that order was limited by the sepa- 

 ration of the Gordiacei, it is not so clear that it is correct to leave Sphaa- 

 rularia in its former position. The principal differences between the 

 two orders (Siebold, " Anat. comp.," t. i., p. 113), as given bySiebold, 

 are that the true Nematodes possess an anus and an organ for copu- 

 lation, while in Gordiacei the one is always, and the other sometimes, 

 wanting. According to both these characters, Sphserularia would be- 

 long to the latter order, in which, accordingly, it is correctly classed by 

 Diesing and Meissner, although V. Siebold, Eudolphi, Owen, and other 



