106 Mr. 11. J. Carter uii the Pi-esence of 



sponge-cell and Trachelius trichophorus^ let us return to the 

 more valid object of the communication, viz. the developmental 

 discovery, as it may be termed, of the spermatozoa in sponges. 



In January, also of 1856 (p. 18, oj). cit.), Lieberkiihn an- 

 nounced his discovery of the spermatozoa in Spongilla, which 

 he states, at the conclusion of the article, to have been pre- 

 viously observed by his respected teacher Johannes Miiller ; 

 and in August of the same year their development is described, 

 accompanied by figures of them separately and within the 

 mother cell (p. 500, pi. xviii. figs. 10 & 15-17, o/j. cit.). They 

 are here represented as minute conical bodies, of which the 

 pointed end is prolonged into a single cilium, but are unac- 

 companied by any measurement. 



From this period up to 1870 1 am not aware that any addi- 

 tional information on the subject was communicated, when, in 

 the October of that year, I published the following account of 

 some spermatic-looking monociliated cells which I found iu 

 Microciona atrosanguinea, Bk. (Annals, vol. vi. p. 339) : — 



" This monociliated body, which may now [July 30th] be 

 seen in great plurality, with every portion of the Microciona 

 torn to pieces for microscopical observation, consists of a 

 rounded triangular head and long cilium [PI. X. figs 17, 18, 

 & 20]. The head is pyriform or shaped like a Florence flask 

 with the neck drawn out to a sharp point or beak, and the 

 cilium attached to the large end, close to which there appears 

 to be a single granule or nucleus ; but in other respects the 

 head is transparent. At first these bodies are in contact with 

 the glass cover, but soon sink to the plane of the slide, about 

 which they move with the head foremost, apparently urged on 

 in a zigzag course by the undulations of the cilium behind. 

 For the most part they are single ; but occasional gToups of 

 four [fig. 19] are seen rolling over the field after the manner 

 of monociliated cells or spermatozoa which want to become 

 separated from each other. When measm-ed, the head, including 

 the beak, was found to be 1 -3000th of an inch long by about 

 1-1 2000th broad at the large end, and the cilium seven times as 

 long as the body, or about 1 -400th inch long. Under the action 

 of iodine, the head became amber-coloured. While portions 

 of Microciona atrosanguinea taken from different localities 

 abounded with this body, together with a number of scarlet 

 gemmules [ova?], in addition to the ampullaceous sacs and 

 monociliated cells of the rest of the sponge, portions of other 

 sponges, even on the same piece of rock, failed to present a 

 similar body when torn to pieces under the microscope. Could 

 this monociliated body with triangular head have been the 

 spermatozoon of Microciona ? " 



