A Supposed New Acineta. 313 



roughness. On one occasion, a Euplotes, who seemed tor- 

 mented by the adhesion of foreign bodies, and by some disorder 

 that produced bumps on his surface, made use of one of the 

 new creatures as a sort of rubbing post. This went on for 

 some minutes without disturbing its repose, but at length 

 the tentacles did retract. 



I was strongly impressed with the idea that the creatures 

 were transition forms, and could not conceive that the stalked 

 cups were made by them in anything like their present con- 

 dition, or that they were ever made by and for an inmate 

 who was destined to remain suspended from their mouths, 

 leaving the greater part of the space waste. I thought they 

 were transition forms of the Cothurnians, and still think so, 

 although I could find no positive proof of the correctness of 

 this view. In some Cothurnians, the edges of the cups were 

 prolonged, and in Fig. 4 the new animal filled the cup better 

 than any others which I saw, and it had something like the 

 remains of a tailfoot. 



The new creatures varied considerably in size, the most 

 common dimensions being about 1-100" from the top of the 

 expanded tentacles to the bottom of the footstalk. The 

 stalks were curved, or straight, indifferently, as were those of 

 the Cothurnians. The normal form was, I suppose, straight, 

 and the curvatures accidental. 



I have called these objects new, because I cannot find that 

 anything exactly like them has been previously described; 

 but the creatures seen by Mr. Alder in 1851 seem to have been 

 in some respects similar, judging from his sketches; though 

 they have been treated as if they differed widely from mine. 

 Mr. Alder's account was published in the Transactions of the 

 Tyneside Naturalists' Field Club, and from thence transferred 

 to the Annals of Natural History, 1851, vol. vii., p. 426. 

 His words are as follows : " While examining a specimen of 

 Sertularia taken from the rocks at Whitburn, under the 

 microscope, I was struck with the appearance of what seemed 

 a very minute parasitic Zoophyte, several specimens of which 

 were attached to different parts of the Sertularia. The body 

 was of a vase or cup form, expanded at the top, and set round 

 with numerous pointed tentacles abruptly thickened towards 

 the base, and forming more than one row ; they had very 

 little motion, but were occasionally bent forward, and the 

 whole were sometimes slowly retracted. The body was 

 attached to the Sertularia by a tolerably short stem." 



In another case he found a smaller one, "the tentacles 

 capitate or knobbed at the end, and not so numerous as in the 

 first." Mr. Alder states that in the first instance he took these 

 creatures for Campanularian Zoophytes ; but u found their 

 organization more simple than in true polyps." 



