THE ROTIFERA OF THE SCOTTISH LOCHS. 181 



D. similis, Stenroos (48). 



This species, distinguished by the great elongation of the second foot-joint, was of 

 rare occurrence in Loch Ness, and has not yet been seen in any other loch. 



Stephanops tenellus, Bryce. (Plate V. figs. 19a, 196.) 



Discovered by Bryce in moss from Spitzbergen (8). The extreme activity of the 

 animal baffled its discoverer in his efforts to secure a portrait. At a later date, when 

 it was found in Loch Ness, I was more fortunate, and subsequently, with the aid of 

 narcotics, obtained the drawings here presented. 



It is very closely related to S. stylatus, Milne (35), of which it is almost an exact 

 miniature. The most important points of difference are, the smaller size, narrower 

 form, narrower and longer jaws, and shorter toes. As Mr Bryce pointed out, under 

 low powers the viscera give the apparent outline of the central parts of the trunk, the 

 hyaline lorica being invisible, and the animal seems more slender than it really is. 

 Both head and lorica are, however, relatively narrower than in S. stylatus. In dorsal 

 view the toes are about ^ °f the total length, those of S. stylatus about ^-. Owing to 

 the strong decurvature of the toes of both species, their actual length forms a greater 

 proportion of the whole than these figures indicate. 



Length, about -g-^-g- inch (110 m). This is larger than Bryce states (3-5-0 i ncn )) but 

 such a lively animal is not easy to measure. After death accurate measurements 

 cannot be made, as under pressure dead examples elongate in a remarkable degree. 

 5. stylatus is nearly twice as long. Many examples contained a well-developed egg. 

 The pair of very long setse are directed upwards as well as backwards. The number 

 of forward-pointing setse is uncertain. The strong motile cilia by means of which the 

 animal runs forward are, both in appearance and mode of action, singularly like the 

 ' legs ' of Euplotes charon and related Ciliata. 



COLURID^E. 



Colurus tesselatus, Glascott (16). (Plate VI. figs. 27a, 27b.) 



A little facetted Colurus found in Loch Morar and Loch Ness belongs, I think, to 

 this species, although it differs greatly in form from Miss Glascott's figures. She shows 

 the lorica, in side view, as triangular, and highest in front ; in dorsal view, as greatly 

 expanded at the posterior angles, although broadest in the middle. 



The animal, as I know it, agrees with Miss Glascott's description as to the tessellated 

 surface, raised at the sutures. It differs in the following points : — The form is that 

 normal in the genus ; in lateral view an evenly rounded back is seen, highest a little in 

 front of the middle, and very little lower at the posterior edge than in front. In dorsal 



