Spermatozoa in the Spongida. 107 



This description was unaccompanied by the figured repre- 

 sentations which I have now added (PL X. figs. 17 to 20), as 

 there was no plate to the paper ; and it was not until I saw the 

 illustrations of Dr. T. Eimer (Schultze's Archiv f. mikroskop. 

 Anat., Band viii. Heft 2, p. 281, 1872) that my attention was 

 again called to the subject, when I recognized in his figures 

 almost fac-similes of my own. 



In the months of March to July 1871, Dr. Eimer disco- 

 vered, both in the siliceous and calcareous sponges, on the 

 shores of the island of Capri, similar bodies to those which I 

 have described and have now for the first time figured, as may 

 be learnt from his descriptions and those he has illustrated 

 from the Calcispongia? (op. et he. cit.). 



Hackel did the same at the island of Lesina in the Adriatic 

 about the same time, viz. in the month of April (Jenaische 

 Zeitschr. f. Med. und Naturw., Bd. vi. 1871, p. 644 ap. H). But 

 he went further ; that is, he not only saw the spermatozoa of 

 certain Calcispongise in their mother cells in situ, but actually 

 saw them entering the ovum of Grantia ciliata, Bk. (Sycortis 

 quadrangulata, H.) (Die Kalkschwamme, Atlas, Taf. 48. figs. 

 6, 7, & 8, and vol. i. p. 396). Thus the fact of spermatoid 

 development and impregnation in the sponges was so far 

 established. 



The shape of the head of the spermatozoon in Hackel's 

 illustrations differs ; for while in most instances it is globular 

 or conical, with the pointed end prolonged into a cilium (like 

 that in Spongilla figured by Lieberkuhn), it is elliptical accu- 

 mulated in Grantia ciliata, Bk., where the. anterior end is 

 extended into a kind of beak ; but in no instances does it 

 resemble that of the bodies figured by Eimer or those described 

 by myself in Microciona and now published. Still, as every 

 living part of the sponge that is soft is subject to polymorphism, 

 no great stress is to be laid upon this difference. 



Taking advantage of Hackel's work on the Calcisponges 

 already mentioned, which is a sine qua non to their study, 

 I sought among our calcareous sponges here for those which 

 might be in an oviparous condition, what in plants we should 

 term in a state of " fructification ;" but it so happens that there 

 is only one here in this state now, viz. Grantia compressa 

 (Sycandra compressa, H.) ; and it also so happens that there 

 are no illustrations of the generative elements of this species 

 in Hackel's work. 



Nevertheless, as this is the commonest and hardiest form 

 here, growing on seaweeds in pools easily got at at every fall 

 of the tide, and well known to me to go through its repro- 

 ductive functions in the months of March, April, and May, so 



