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 provided 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 Batrachidee, was 
described by me in the Catal. Fish. iii. p. 174, with a single species, 
Thalassophryne maculosa. The typical specimen being small and 
having been in spirits for a long time, I did not observe the openings 
in the venom-spines, 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 10% inches long. 
Fig. 1. Hinder half of the head, with the venom-sac of the opercular apparatus in 
situ. * Place where the small opening in the sac has been observed. a. La- 
teral line and its branches. 0. Gill-opening. c. Ventral fin. d. Base of 
pectoral fin. e. Base of dorsal fin. 
Fig. 2. Operculum, wit the perforated spine. 
