156 DR. A. GUNTHER ON A POISONOUS FISH. _ | Mar. 22, 
snakes. This genus, belonging to the family of Batrachide, 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 above (p. 150) as Thalassophryne reticulata. 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. 4%. Gill-opening. c. Ventral fin. d. Base of 
pectoral fin. e. Base of dorsal fin. 
Fig. 2. Operculum, with the perforated spine. 
e 
The structure of the poison-organ is as follows :— 
1. The opercular part.—The operculum is very narrow, vertically 
styliform, and very mobile; it is armed behind with a spine, eight lines 
long, and of the same form as the venom-fang of a snake; it is, how- 
ever, somewhat less curved, being only slightly bent upwards; it 
has a longish slit at the outer side of its extremity, which leads into 
a canal perfectly closed, and running along the whole length of its 
interior; a bristle introduced into the canal reappears through an- 
other opening at the base of the spine, entering into a sac situated 
on the opercle and along the basal half of the spine ; the sac is of an 
oblong-ovate shape, and about double the size of an oat-grain. Though 
the specimen had been preserved in spirits for about nine months, it 
