Discovery of Poison Organs in Fishes. 257 



the fish, and that it is by the mucous glands that the fluid is 

 secreted.* The dorsal spines were found to be furnished with 

 precisely similar contrivances. 



Nobody, says Dr. Giinther, will imagine for a moment that 

 this complicated apparatus can be intended for a harmless 

 purpose, or to emit an innocuous fluid into a wound. 



This example of a special poison-organ in fishes, although an 

 isolated one, is, nevertheless, of the highest importance, as the 

 muciferous system supplying these glands is common to the 

 whole class of fishes, and though not quite clearly demonstrated 

 by a good anatomical examination, yet there are doubtless many 

 others which will have to be added to the number ; and just as 

 in the class of Ophidia, we have some snakes with poisonous 

 saliva and some quite innocuous, so we shall also find it to be 

 with the mucous secretion of fishes. 



It must also be borne in mind that these fish-spines are 

 merely weapons of defence ; all the Batrachoids with obtuse 

 teeth upon the palate and lower jaw, feeding upon mollusca 

 and Crustacea. 



Explanation op Figuee op Thalassophryne reticulata 

 prom the Pacific Coast op Panama, 1-4th Natural Size. — 

 a a, The opercular spines seen projecting from the sides of the 

 fish, just above the gill openings. h b, The dorsal spines, 

 c c, The mucous canals, which traverse the entire length of 

 the fish on each side. A. The opercular spine seen separately 

 (natural size) . The openings to and from the canal by which 

 the poison is introduced into wounds are indicated by arrows. 

 B. The same spine with the poison-sac or reservoir attached, 

 showing (d) the small orifice by which the poison is conveyed 

 to the sac from the muciferous system, with its free end lying 

 within the sac. 



* The two specimens of Thalassophryne, being distinct species, and at present 

 the only existing types, have not been injected or dissected further to de- 

 monstrate this point, but more specimens from Panama are shortly expected, and 

 ■when these arrive, injections of the glands will be properly made. 



