298 



VENOMS 



ing the cannelures and the skin, which is distended to allow it to 

 pass. 



Towards the base of the spine, the edges of the cannelure are 

 united, and form a hollow, bony cone, the walls of which are lined 

 with the cells that secrete the toxic fluid. 



Greater Weevers are 

 usually from 12 to 30 cm. in 

 length, and of a reddish or 

 yellowish-grey colour, with 

 blue or violet spots. They 

 are caught in trawls and are 

 fairly common on sandy 

 bottoms. In the month of 

 June they approach the shore 

 for the purpose of spawning. 

 The venom of the Weever 

 has formed the subject of 

 interesting studies by Giin- 

 ther, Gressin,^ Bottard, 

 Phisalix,^ and more recently 

 by Kobert^ and A. Briot.* 



In order to procure suffi- 

 cient quantities of it for ex- 

 perimental purposes, Briot 

 cuts off the venomous spines and the surrounding tissue with a pair 

 of scissors ; he then pounds the whole in a mortar, and mixes the 

 pulp with pure glycerine. After filtration through paper, a toxic 

 solution is obtained, which does not deteriorate by keeping, and is 

 neutral to litmus. 



Pig. 108. — A, Operculum and opercular spine 

 of the Lesser Weever (TracMnus vipera) ; ar, 

 articular surface of the operculum ; c. op, body 

 of the opercular spine ; c. an, canal of the 

 spine ; z, space occupied by the poison-gland. 

 B, Spine belonging to the first dorsal fin ; c. an, 

 efierent poison-canal in the spine. 



' TMse Paris, 1884. 



' Bulletin du Museum d'histoire naturelle, 1899. 



' " Giftfische und Fischgifte," Vortrdge im Bostoaker Fischerverein, 1902, and 

 Die medizinische Wochensahrift, 1902. 



' Comptes rendus de la .SoCiHe de Biologie, October 25 and November 8, 1902, 

 and June 21, 1904 ; Journal de Physiologie, March, 1903. 



