Tatem, on a New Species of Microscopic Animals. 31 



form, and terminating posteriorly in a short filament, by 

 which their swimming movement was mainly effected; the 

 other extremity was blnut, and the body, which was con- 

 siderably longer than the filamentous tail, contained nume- 

 rous minute granules, and appeared somewhat flattened. 

 These creatures moved very actively, and to a considerable 

 distance, swimming about and gliding among the detached 

 portions of epithelium with great celerity. They bore not 

 the most distant resemblance to the spermatozoa contained 

 in the ovotestis, nor were they at all like the detached parti- 

 cles of columnar epithelium found elsewhere. They were 

 immediately dissolved by acetic acid, leaving a granular 

 amorphous residuum. Gratiolet (' Journ. de Conch.,' vol. i, 

 1850, p. 116) states that the spermatozoa undergo a meta- 

 morphosis; and that the different forms met with in the 

 spermatheca, and which are generally spoken of as animal- 

 cules, are really altered spermatozoa. Other writers have 

 failed to trace this metamorphosis. The additional tube of 

 the spermatheca, when examined in individuals immediately 

 after copulation, contained the sperm atophore ; at other times 

 it contained free spermatozoa or animalcular bodies, and 

 sometimes only detached epithelial cells. 



The multifid vesicles were lined with coarse granular epi- 

 thelial cells, having large nuclei, and contained granules, 

 which had a tendency to run into chains, and large trans- 

 parent cells, in which other cells might be seen in different 

 stages of growth. 



The frequent absence of the dart from its sac has been 

 already noticed. It is worthy of remark, that the darts re- 

 ceived from another individual are very commonly found at 

 the base of the tongue-shaped gland, and when so found are 

 discoloured and partially destroyed. 



On a New Species o/ Microscopic Animals. 

 By T. G. Tatem, Esq. 



(Read December 11th, 1867.) 



The marine form of Epistylis represented in PI. VI, fig. 5, is 

 sufficiently subversive of the statement that Epistylidese ''are 

 found exclusively in pure water on aquatic jilants or animals" 

 (' Pritchard's Infusoria,' p. 589). It may, however, possibly 

 prove to be merely a fresh-water form, modified by its marine 



