104 Dr. A. C. Stokes on new Hypoirichous 



of the body is translucent, while from the anterior end a bar 

 of rich reddish orange proceeds backward a short distance 

 behind the epipodia. The tip of the tail again is flecked 

 with reddish-brown pigment-grains. As Pallas first noticed, 

 the muscular bands of the epipodia are so arranged as to give 

 the organs the aspect of a file or rasp, as in Cymbulia, from 

 their intimate decussation, and their mobility is remarkable. 

 The animals mount gracefully from the bottom of the vessel 

 and steer for the surface, or in a circle, the tips of the epi- 

 podia almost touching ventrally and again dorsally — just as 

 a lithe swimmer would do in the erect position in the water 

 by alternately touching the tips of his fingers in front and (if 

 he were able) behind. In the case of Clwne, however, the 

 locomotive organ is a broad muscular wing on each side, the 

 curves of which so strike the water as to cause the easy grace- 

 ful motion so characteristic of the species. 



The only Pteropod hitherto found on the eastern shores of 

 Scotland is Spirialis retroversus, Flem., which occasionally 

 occurs in vast numbers, as mentioned in the February num- 

 ber of this journal *. It is equally abundant on the western 

 shores. So rare are other forms that in our experience only 

 one other species has been met with, viz. that termed by 

 Dr. Gwyn Jeffreys Clio pyramidata, Browne, which had 

 been carried by the Gulf-stream in August to a quiet bay in 

 North Uist. 



X. — Some new Byfotriclious Infusoria from American Fresh 

 Waters. By Alfred C. Stokes, M.D. 



[Plate m.] 



Litonotus vermicularis, sp. nov. (PI. III. fig. 1.) 



Body elongate, flattened, from fifteen to twenty times as long 

 as broad, soft, flexible, and elastic, widest centrally, tapering 

 thence to the rounded posterior extremity, and anteriorly to 

 the subapical constriction ; the frontal border obliquely 

 rounded; ventral surface longitudinally striate ; dorsal aspect 

 ordinarily traversed by a narrow, longitudinally disposed, 

 keel-like ridge; contractile vesicles multiple, thirty or more 

 arranged in a single series near one lateral border, from eight 

 to ten scattered and disposed near the opposite lateral margin ; 



* ' Annals/ Feb. 1887, pp. 140-141. 



