108 Mr. 11. J. Carter un the Presence of 



as to become effete and disappear for the most part in June 

 (eaten both inside and out by small Crustaceans), it has 

 afforded me abundance of opportunities of witnessing what 

 Hackel has so truthfully and lucidly described and illustrated 

 of several other species in his work. 



Yet in only one instance have I been able to see what 

 appeared to me to be the spermatozoa of the species, and then 

 not living but scattered dead about the field in considerable 

 number (fig. 21). 



These bodies, comparing small things to great, were shaped 

 like a sky-rocket, with a long cilium (figs. 22 & 23) ; the 

 head conical and based on the body, which Avas somewhat 

 constricted at the point of union, and slightly increasing back- 

 wards to an obtuse end, from which projected the cilium. The 

 head and body together measured l-6000th of an inch long, by 

 about 1 -24000th of an inch thick ; and being divided into three 

 parts, the body appeared to be just twice as long as the head. 

 The cilium was 10-6000ths of an inch long. 



Had these bodies been active and living instead of still and 

 dead, I probably, from their minuteness, should not have been 

 able to obtain the measurements ; but, as it was, these with the 

 form were too plain to be mistaken, although the general 

 opacity of the body obscured all difterentiation in its composi- 

 tion. 



That they were not the disintegrated ectodermal cells of the 

 embryo [Planula or Gastrula), the attachment of the cilium to 

 the longer portion (that is, the body) instead of to the shorter 

 one or head (according to Hackel's figm-es of these cells), 

 seems to point out ; besides, the latter was conical and pointed, 

 not obtuse and round like the outer or monociliated end of 

 the ectodermal cell. Again, they could not have been dead 

 long, or they would have vanished by " difiluence ;" wdiile the 

 adhesive sarcodal composition of the ectodermal cells seems to 

 defy any separation of them into individuality, although I 

 often tried to produce it. 



Of course I can only state and show what these bodies 

 were ; for although they may look very much like spermatozoa, 

 yet, seeing them enter the ovum is the only proof that they 

 are such and do belong to the sponge. 



I have also observed another monociliated body in a fresh 

 specimen of Halisarca Dujardinii, equally pregnant Avith ova 

 as the Grantia compressa, but not so far advanced (figs. 24 & 

 26, a-i). It was circular in form, like a coin with a rounded 

 thick obtuse edge, diminishing to extreme thinness towards the 

 centre, where there appeared to be a single granule, the rest 

 of the body being homogeneous. From some part, whether 



