neio or little-known Infusoria. 211 



Descr. I have waited so long with the description of this 

 species, which I found in the White Sea in 1879, that it has 

 at last been described by M. A. Gruber, not long since, under 

 the name of CotJmrnia socialis. And I do not regret it ; for I 

 should never have described the species, with all the details 

 given by M. Gruber ; and, further, it would never have re- 

 ceived from me the specific name ^' socialis,^^ as I only came 

 across it in St. Petersburg among Bryozoa preserved in 

 alcohol, and I have only seen a single solitary individual, 

 whilst the German zoologist has seen it in the living state 

 and in great numbers. I have no doubt, however, on 

 comparing my individual with the figures given by M. Gruber, 

 that they belong to the same species. All the characteristic 

 details of the species are present, except perhaps the coloration, 

 which in the individual observed by me is not yellow, it is 

 entirely colourless ; but, as I have just remarked, the animal 

 that I have observed is solitary, and therefore still very 

 young, and it may very well be that the absence of colour is 

 due simply to the youth of the animal. I would also call 

 attention to the extreme regularity of its form. 



The specimen that I have examined was attached to a 

 Bryozoan by means of a rather long, slender, solid peduncle, 

 slightly inflated at its base. The carapace, which is about 

 the same length as the peduncle, is of an ovoid form, with a 

 small conical process at the lower part, and with a funnel- 

 shaped neck at the upper part. The carapace bears four very 

 strongly marked circular strise or grooves, dividing it into five 

 parts or segments. The body of the animal is placed upon a 

 small peduncle, which is only the continuation, in the interior 

 of the carapace, of the exterior peduncle. 



The following are some measurements of this marine 

 species, which, apparently, is characteristic of the northern 

 seas ; for it is only in these that it has been found, by two 

 observers : — 



millim. 



Length of the carapace 0"084 



Maximum breadth 0'035 



Length of the peduncle 0'054 



Tintinnus mediterraneus^ sp. n. 

 (PI. XII. figs. 1, 2.) 



Diagn. Concha urceoli inflati forma, paulo longior quam 

 latior, collo brevi lato, 4-5 striis annulatis. * 



Loc. Mediterranean Sea, Black Sea, Crimea, and Bay of 

 Naples. 



Descr. The carapace of the animal, which is all that I have 



16* 



