FAUNA OF THE CHESS AND GADE. 341 



Naturhist-Med. Ver. Heidelberg, vol. 7, 1903, pp. 529-621, of 

 which I have seen extracts only) he concluded that these 

 variations are mainly due to differences in the nature of the 

 waters and to seasonal variations of temperature. He found, 

 e.g. that, during the winter months, the long-spined forms were 

 obtained, and, during the late spring and summer months, 

 the short-spined and spineless forms. The specimens so far 

 examined by me had posterior spines about as long as that of 

 the type-form, and showed only trifling differences in length. 

 They were obtained, as above stated, in the months of April, 

 May, and October, but the observations made are insufficient to 

 decide to what extent the species varies in the country of the 

 Chess and Gade. 



18. Bracluonus pala, Ehren. — This species has been found 

 in the pools of Chipperfield Common and Kings Langley Lodge, 

 and, quite recently, in vast numbers in Coxpond, between Lever- 

 stock Green and the Saracen's Head, on the way to Hemel 

 Hempstead. The specimens examined usually swarm forwards 

 rapidly, turning slowly about the long axis of the lorica, but 

 some remained anchored for a long time. They differed greatly 

 in the frequency with which they extended their flexible feet and 

 lashed out with these. Most of them swam about for a long 

 time without extending their feet, others did so occasionally, 

 and only a few frequently ; a very little cocaine solution soon 

 caused frequent extension. The structural features of this 

 Eotifer were always well seen, its four, strong, tapering, and 

 sharp oral spines, cervical bright red eye, and powerful masti- 

 catory apparatus being especially conspicuous. In some speci- 

 mens, obtained from Kings Langley Lodge Pool on April 13th, 

 1914, the eye-spot was exceptionally bright, and there appeared 

 to be a faint pink coloration in the neighbouring oral parts of 

 the Eotifers. 



By far the greatest number of specimens of B. pala was 

 obtained from Coxpond on July 14th, 1914. There have been 

 other occasions on which an exceptionally large number of 

 specimens of a species has been obtained, e.g. on October 3rd, 

 1913, when a vast number of B. rubens was found in the pool on 

 the eastern side of Potten End, and on May 26th, 1914, when a 

 great number of Anuraea brevispina was dredged from Hastoe 



