2^6 



VENOMOUS ANIMALS 



Section 2. — Poison Apparatus Partially Closed. 



The types of this section are Thalassophryne reticulata Giinther, 

 which is found near Panama, and T. maculosa Giinther, wliich is 

 chiefly found in the Gulf of Bahia (Brazil). 



In these fish the poison apparatus is double, there being hollow 

 barbs on the gill covers and on the back close behind the head. 

 The barb on the gill cover, which is bent somewhat upwards, is 

 conical in shape and pierced by a central canal, which is connected 

 with a poison reservoir situated at the base of the barb. The cells 

 lining this sac are probably those which secrete the poison. The 

 venom, therefore, is capable of flowing along this canal without 

 being forced by muscular exertion. The barbs on the dorsum of the 

 fish consist of two spines pierced, as in the case of the opercular 

 spine, by canals which communicate with poison reservoirs. When 

 the barbs are erected, the poison flows out of the peripheral openings 

 of the central canals, and thus can enter any wound caused by them. 

 The nature of the venom and its physiological action are not known, 

 but it is supposed that it will be like Synanceia and Trachinus, 

 though there is no ground for this supposition. 



The poison apparatus of Batrachus tau of the waters of North 

 America and B. grunniens of those of the Antilles are said to be 

 identical (Calmette) with that just described for Thalassophryne. 



Section 3.^ — Poison Apparatus in more or less Direct Com- 

 munication with the Exterior. 



This section contains a number of fish, the best studied of which 

 is Trachinus draco. 



Trachinus draco. — This fish possesses two- sets of poison appa- 

 ratus, the one a barb on the operculum, and the other connected 

 with the dorsal fin. The barb on the operculum possesses a groove 

 which is converted into a canal by a fine membrane, which leaves 

 an opening near the point of the spine. This barb, which is slightly 

 erectile, pierces the operculum. At its base lies the poison gland, 

 partly covered by an adductor muscle, which helps to press the 

 poison into the canal and to erect the spine. When the barb enters 

 the flesh of another animal, the above-mentioned membrane is 

 stripped off and the poison enters the wound. 



The dorsal apparatus consists of from five to seven spines joined 

 together by a membrane, which is adherent almost to their tips. 

 Each barb has a deep double channel, the two grooves of which 

 join towards the base of the spine, and form a conical space, of 

 which the walls are covered with cells which secrete the poison. 



The first symptoms are very severe pain of a burning or lancinat- 

 ing character. The part then tingles and becomes painfully numb, 

 and this may spread along the limb, and appears to travel along 

 the nerves, though the joints are particularly tender. This is 

 followed by palpitation, fever, delirium, vomiting, and syncope. 

 The area affected becomes swollen and inflamed, and if neglected 



