Dinocharis Collinsii. 271 



of the present year, Miss S., who had been spending a few- 

 weeks with us, again took away a bottle full of the water from 

 the same pool. We had searched it well while she was here, 

 but could find nothing of particular interest. After she had 

 kept this bottle of water, however, for more than four months, 

 she suddenly found it swarming with these interesting crea- 

 tures. I may add that about three weeks ago [at the end [of 

 July] I obtained water from the same place, but could not then 

 find anything of interest. Some of the drains leading to the 

 little pond had been cleaned out during the course of the 

 summer, which may possibly account for the absence of the 

 Rotifer a." 



In captivity our little Dinocharis is active, rarely still, 

 rooting among the sediment, or swimming with a smooth, 

 gliding motion, of no great speed. If I may judge of its 

 behaviour in freedom from what is seen while under our notice, 

 it seems to be specially a bottom-frequenting form; for, in 

 a phial, the pocket lens never detects it roaming freely through 

 the water, while a pipette thrust down to the sediment inva- 

 riably captures several specimens. I am not acquainted with 

 any other form in the class with which this well-armed species 

 can possibly be confounded, unless it be the Polycheetus sub- 

 quaclratus of M. Perty, figured (without any description) in 

 Dr. Arlidge's Infusoria, Plate xxxviii., figs. 31, 32. To this 

 species there is certainly much resemblance, but at the same 

 time much dissimilarity, particularly in the shape of the lorica, 

 the number of long medial spines (eight in Polycheetus) and in 

 the situation of these, which are represented on the ventral 

 surface. This, however, may be mere inaccuracy of obser- 

 vation. Indeed, considering all things, I would not be quite 

 sure that this form of Perty's was not founded on our Dino- 

 charis, very carelessly and untrustworthily delineated. Should 

 it, however, prove to be so, M. Perty's name cannot be re- 

 tained, since there can be no ■ doubt of the generic affinity of 

 our species with the other members of Dinocharis, Dr. Leydig, 

 indeed, supposes Perty' s Polycheetus to be a crustacean ; but in 

 this he is certainly mistaken. 



EXPLANATION OP THE PIGUEES. 



Pig. 1. Dinocharis Collinsii; dorsal aspect. Fig. 2. Ibid, 

 ibid, (the armature of the lorica omitted, in order to a clearer 

 display of the viscera). Fig. 3. Ibid., lateral aspect. Fig. 4. 

 Ibid., outline of transverse section of lorica. 



Postscript. — I subjoin a list of Rotifera, which Dr. Collins 

 has detected in the tiny pool above-mentioned, remarkable, not 

 only for the number, but for the rarity of the species, as will 



