Dinocharis Oollinsii. 269 



DINOCHARIS COLLINSII ; A ROTIFERON NEW 

 TO SCIENCE. 



BY PHILIP HENEY GOSSE, P.E.S. 

 (With a Coloured Plate.) 



Class Rotifer a. Fam. EucJilanidota. 



Gen. Dinochaeis (Ehrenb.). "Eye single, cervical: foot 

 forked : lorica closed ventrally, with, the lateral margin sharp." 



Sp. D. Gollinsii (Gosse). Lorica about as broad as long ; 

 furnished with four spines at the posterior edge, and four longer 

 ones in the centre of the back : front and lateral margins den- 

 ticulate. 



Description : — Total length, when extended in swimming, 

 "008 inch; length of lorica along dorsal line, '0032; ibid, to 

 tips of posterior spines, "004 ; breadth of lorica, '0038. The 

 lorica, viewed dorsally, has a somewhat square outline, with, 

 rounded angles; the front hollowed, the posterior edges 

 nearly even, but set with four spines directed backwards, of 

 which the dorsal (and inner) pair slant diagonally upwards 

 and outwards, the ventral (and outer) pair are nearly in the 

 line of the body. The dorsal surface is much arched longi- 

 tudinally, particularly the anterior half (See Fig. 3), the 

 highest point being about one-third from the frontal exca- 

 vation. From this highest point spring two stout, long, rigid, 

 slightly decurved spines, rather wide apart, and point back- 

 ward almost horizontally. Another pair, very similar, arise 

 from a more central point, close together, but diverge towards 

 their tips. The lateral margins of the lorica are beset with 

 small spines, about twenty-five on each side, like the teeth of a 

 circular saw, the seventh, eighth, ninth, and tenth being larger 

 than the rest. The frontal excavation is similarly toothed, but 

 much more minutely. The whole ventral surface is delicately 

 puctulate ; the dorsal surface only in the central region, where 

 the punctuli have a tendency to run in convergent rows. The 

 ventral surface is wholly closed, so that the lorica is testu- 

 diniform. It is strongly convex in transverse section (See 



The head is quite retractile, thick, and massive in form, 

 sub-cubical, with rounded angles ; the lateral edges appear to 

 become shelly, carrying two or three rows of small spinous 

 teeth. The occiput forms a shelly projection, also edged with 

 rows of teeth (See Fig. 1) ; this, though nearly lost in the 

 general outline, when the head is fully extended, yet is often 



