422 PROF. F. J. BELL ON THE TEMNOPLEURID^. [Juiie 1, 



Barcelona. It having been stated by some gentlemen who heard 

 Professor Huxley's paper read, that Crayfishes were certainly supplied 

 to the Madrid market, I was led to move some of my Spanish friends 

 to make careful inquiries as to the localities whence these Madrid 

 Crayfishes are obtained. The result showed that they are procured 

 in considerable numbers at only a short distance from Madrid itself. 

 The Crayfish appears to be unknown in the rivers Douro and Tagus, 

 on the western side of the Peninsula, and in the Ebroon the eastern ; 

 but it is found abundantly in the Talegones and Escalote, rivulets 

 forming part of the sources of the Douro, in the Henares, one of 

 the sources of the Tagus, and in the upper part of the Jalon, an im- 

 portant tributary of the Ebro. Widely separated, however, as these 

 three rivers become in their courses to the sea, both east and west, 

 the rivulets I have mentioned as forming tiieir principal sources all 

 take their rise within an area probably not more than twenty miles 

 square, situated nearly in the centre of Spain, and about forty or fifty 

 miles north-east of Madrid. It is from these small streams that the 

 INIadrid market is supplied by fishermen of Alhama, Siguenza, and 

 Berlanga ; and these streams are the only ones well within the 

 borders of the Peninsula in which, so far as I can discover, the Cray- 

 fish is to be found. As before mentioned, Crayfishes are said to be 

 found about Barcelona ; but it may possibly turn out that they are 

 really caught in the small streams which, rising in the Pyrenees, 

 afterwards unite to form the river near which Barcelona stands. 

 My correspondents tell me that they can obtain no information of 

 the occurrence of the Crayfish south of Madrid ; and they add that 

 if tliey were known to be found there the markets of the capital 

 would not be solely supplied from the northern streams, as is now the 

 case. The peculiar localization of these crustaceans in the centre of 

 Spain suggests the idea of their having been specially introduced ; but 

 experiments in acclimatization are, I believe, unknown in the Penin- 

 sula ; and without attempting any explanation of the difficulty, I may 

 simply record the fact that the Crayfish is abundant in the rivulets 

 within the limited area I have mentioned. 



2. Observations on the Characters of the Echinoidea. — III. 

 On some Genera and Species of the Temnopleuridce. By 

 F. Jeffrey Bell, M.A., F.Z.S.^ Professor of Comparative 

 Anatomy in King's College. 



[Eeceived April 24, 1880.] 



(Plate XLI.) 



For the purposes of present convenience I adopt the name Tem- 

 nopleuridcB for those forms which are grouped under it by Prof. 

 Alex. Agassiz in his ' Eevision of the Echini.' I need not now de- 



