26.j 



Rattulus Collarts sp. n. and some other Rotifers. 



By Charles F. Rousselet, F.R.M.S. 



(Read March 20th, 1896.) 



Plate XI. 



In November of last year I paid a visit to the bog ponds near 

 Sandhurst, which many years ago yielded such an abundance 

 of new and rare Rotifers to the patient researches of Dr. Collins 

 and Mr. Gosse. These small ponds, averaging only about a 

 square yard or two in extent, and quite filled with sphagnum 

 moss, are still as prolific now as they were thirty years ago, and 

 I obtained therefrom quite a number of rare Rotifers, includ- 

 ing Cojpeus spicatus, Microcodon clavus, (Ecistes velatus, with 

 two red eyes near the edge of the corona, and Mr. Gosse's 

 Diplo'is propatula, which Dr. Collins originally discovered in 

 these ponds. This animal is identical with the Euchlanis subversa 

 described by Mr. D. Bryce in " Science Gossip," L890, p. 77. 

 Dr. Collins' figure, which is reproduced in Hudson and Gosse's 

 book, PI. XXIV., Fig. 2, is perfectly correct, and represents the 

 animal when focussed on the inangulation formed by the 

 dorsal and ventral plates. Unfortunately Mr. Gosse has mis- 

 interpreted the structure of the lorica, which certainly is very 

 unusual, and in fact closely approximates that of an ordinary 

 Euchlanis turned upside clown. There can be no doubt, how- 

 ever, that the dorsal plate is small and concave, and the ventral 

 plate much larger and convex, with a deep inangulation between 

 them, and there is no dorsal cleft. This makes the animal a 

 Euchlanis, as pointed out by Mr. Bryce, and as it is now ascer- 

 tained that these two names refer to one and the same animal 

 the proper name for it must be Euchlanis propatula (Gosse). I 

 sent some specimens to Dr. Collins, who at once recognised them 

 as the animals he had figured in his sketch book thirty years 

 ago, and this removes all possible doubt on the subject. Dr. 



Journ. Q. M. C, Series II., No. 89. 19 



