NATURAL HISTORY — ZOOLOGY. 223 



district of "West Africa, by one of the natives, to the Rev. Mr. 

 Baillie, by whom it was presented to Mr. Murray. It is characterized 

 by three salient horny processes on the head. Many lizards have 

 singular spiny projections on all parts of the body ; but this very well 

 marked species has not been hitherto recorded. In allusion to the 

 prongs on the head, Mr. Murray named it Chameleon tricornis. 



BRITISH WELL SHRIMPS. 



The Rev. A. Hogan has exhibited to the British Association 

 specimens of some remarkable additions not long since made to our 

 British Crustacea. They consisted of two species of Nephargus 

 (Fontanus and Kochianus), and the new genus, Crangonyx, with its 

 single species Subterraneus of Spence Bate. These species have been 

 described and figured in the volume of the Natural History Beview 

 and Quarterly Journal of Science for 1859. They are of great 

 interest, as examples of a subterranean Fauna in England, analogous 

 to that long ksown on the Continent and in America. The first 

 established instance of the occurrence of Niphargi in England was 

 Mr. West wood's discovery at Maidenhead, Berkshire, of a well con- 

 taining numbers of iV. aquilea. They have, more recently, been 

 obtained from Corsham and Warminster, Wiltshire, and also from 

 Ringwood, on the borders of the New Forest, Hampshire. Cran- 

 gonyx subterraneus has occurred at the two latter places, but not at 

 the first named. Niphargus fontanus is found at both Corsham and 

 Ringwood, but with a difference in the shape of the gnathopoda and 

 posterior ploopoda, amounting to a probably distinct variety, if not 

 species. The form of the gnathopoda, or hands, is worthy of atten- 

 tion, being each armed with a moveable claw of large size, forming a 

 prehensible organ of great power. N. fontanus is also possessed of 

 small, yellow eyes, which distinguish it in a very marked way from 

 the allied species (of the genus Gammarus) found on the Continent. 

 Every member of the subterranean Fauna hitherto found has been 

 destitute of eyesight. The movements of Niphargi, when kept in 

 captivity, are interesting to observe ; but Mr. Hogan states that he 

 has found great difficulty in preserving them alive. The longest 

 period during which even the strongest specimen survived its capture 

 was three weeks. The average temperature of the water in which 

 Niphargus and Crangonyx are found is about 50° Fahr., and they 

 seem to propagate in recently-formed wells as freely as in old ones. 

 In no case have any species of this family been found, either in this 

 country or abroad, in open wells or other than artificial ones,— * 

 pumps, in fact. They are found at all seasons of the year, but most 

 abundantly towards the end of the autumn. The largest size known 

 among the English species (that of N. fontanus) hardly exceeds half 

 an inch. Mr. Hogan hoped that more extended observations would 

 be made in Great Britain on this interesting family of Crustacea, as 

 their economy and structure are as yet very imperfectly known, and 

 an accurate examination would be sure to reward the investigator 

 with results at least as interesting as those already obtained regard- 

 ing their allies by continental naturalists. Mr. Westwood stated 



