ox THE EOEINIATIOX OE THE EGG IN THE ANNULOSA. 
625 
which the tubules open, contains also large nucleated cells. I am bound, however, to 
admit that I much doubt whether these nucleated cells do really perform any part in 
the act of fertilization, since, though I know them well by sight, and though I have 
over and over again found the hair-shaped spermatozoa in the generative organs of the 
female, I have never met with any of the round cellular bodies in this situation. 
In lAthoMus, also, and Geo^hilus, Stein* discovered, besides ordinary hair-formed 
spermatozoa, large cellular bodies, which he believes to be actively concerned in impreg- 
nation. But in the spermatic sacs of the female of Lithohius jpilicornis^ I found only 
the long hair-like sort; and it would appear, from what Fabre saysf, that in the extra- 
ordinary silken nests discovered by him, and in which, reversing the usual order of things, 
the male lays its semen, that excellent observer found only the capillary spermatozoa. 
The spermatophores of Cryptops, however, contain, besides the filiform spermatozoa, 
numerous oval bodies much resembling the spermatozoa of Glomeris ; and though these 
may possibly have some function like that wdiich has be m attributed to the second sort 
of cells found in the spermatophores of the Calanoid Em unostraca, it has not yet been 
proved in either case that they are not homologous with spermatozoa. I may refer to 
w’hat I have already said respecting Chelifer and Ohisium%, as tending to show that in 
these genera also a similar state of things exists. 
I believe there are no other animals among the Annulosa in which two sorts of 
spermatozoa are at present Imowm to occur ; but it is evident that there may be many in 
which the difierence, being slight, has not been observed ; wfithout, however, pushing this 
argument too far, it may fairly be doubted wdiether we are justified in assuming that the 
hair-shaped spermatozoa of Isopods, Insects, and Chilognaths are strictly homologous 
with the more or less spherical spermatozoa of most Crustacea and of the Chilopods ; 
and whether it would not be more correct to correlate the hair-shaped forms Avith the simi- 
larly-shaped spermatozoa of lAtliohius, Asellus, &c., and the cellular types with the less- 
elongated bodies found in the male generatiA'e organs of these interesting genera. 
When two sets of spermatozoa are present, it is not unreasonable to suppose that 
their functions are different, and it would be of the highest interest to ascertain wherein 
this difierence consists. The question has often occurred to me Avhether the two sorts of 
spermatozoa produce embryos of different sexes. It seems to be satisfactorily ascertained 
that the sex of the Hive-bee depends on the impregnation of the egg, though, on the 
other hand, no such connexion appears to exist in Psyche. In the Hive-bee the unimpreg- 
nated egg produces only a male embryo. But if in any species the reverse were the case, 
and the unimpregnated egg always produced females, and if, further, at any one time it 
so happened that no males nor any impregnated females AA'ere in existence, it is evident 
that the male sex Avould be extinct for ever. Such cases we have perhaps in the species 
of the genus Cynips, although in spite of the great amount of negative evidence, it is 
difficult not to believe that the males do really exist in this genus, and will sooner or 
later be discovered. 
* Loc. cit. p. 252. t Loc. cit. p. 305. 
+ On a future occasion I shall attempt to show that the same is the case with the Sminthurid*. 
