Dr. A. Giinther on a Poison-organ in a Batrachoid Fish. 459 



On the other hand, I have heard of so many positive facts from 

 highly educated travellers and excellent observers (some of whom, 

 being medical men, had treated cases of this nature), that it appeared 

 to me necessary to give every attention to this subject. Especially 

 it seemed probable that a sac with a more or less wide opening in 

 the axil of the pectoral fin of many Siluroid and of some other fishes 

 would contain a fluid which might be introduced into a wound by 

 means of the pectoral spine, which would be covered with it, like the 

 barbed arrow-head of a bushman. 



Whether this secretion is equally poisonous in all the species 

 which are pronded with that axillary sac is a question which can 

 only be decided by experiments made in the tropics ; but I can hardly 

 doubt its poisonous nature, after discovering in a genus of fish a 

 poison-organ which structurally is the same as in the venomous 

 snakes. This genus, belonging to the family of Batrachidse, was 

 described by me in the Catal. Fish. iii. p. 174, with a single species, 

 Thala99ophryne maculosa. The typical specimen being small and 

 having been in spirits for a long time, I did not observe the openings 

 in the vcnom-spmes, although I now perceive them to be present, as 

 in the second species found by Messrs. Dow and Salvin, which I 

 have described (in P.Z.S. 1864, p. 150) as Thalassophryne reticu- 

 lata. The specimen is 1 0^ inches long. 



Fig. 1. Hinder half of the head, with the venom-sac of the opercular apparatus in 

 ritu. * Place where the small opening in the sac has been observed, a. La- 

 teral line and its branches. *. Gill-opening, c. Ventral fin. d. Base of 

 pectoral fin. e. Base of dorsal fin. 



Fig. 2. Operculum, wit'i the perforated spine. 



