68 



DANGEROUS MARINE ANIMALS 



Catfish, Heteropneustes fossilis (Bloch) (Fig. 37, Next to Bot- 

 tom). Found along the coasts of India, Ceylon, and Viet Nam. 



Oriental Catfish, Plotosus lineatus (Thunberg) (Fig. 37, Bot- 

 tom) . Occurs in the vicinity of river mouths throughout much of 

 the Indo-Pacific area. 



Sea Catfish, Bagre marina (Mitchell) (Fig. 38). Inhabits 

 the east coast of America from Cape Cod to Rio de Janeiro, Brazil. 



SPINY DORSAL FIN 



SOFT DORSAL FIN 



CAUDAL PEDUNCLE 



CAUDAL 

 FIN 



OPERCULUM 

 OR GILL COVER 



PELVIC 

 OR 

 VENTRAL FIN 



Fig. 39. Drawing showing the external anatomy of a true fish. Note the 

 names of the various fins to which venom organs are sometimes attached. 



Venom Apparatus of Catfishes. Venomous catfishes have a single, 

 sharp, stout spine immediately in front of the soft-rayed portion of 

 the dorsal and pectoral fins (Fig. 39). These spines are enveloped 

 by a thin layer of skin, the integumentary sheath, which is con- 

 tinuous with that of the soft-rayed portion of the fin. There is no 

 external evidence of the venom glands, which are located as a series 

 of glandular cells within the outer, or epidermal, layer of the in- 

 tegumentary sheath. The venom, or glandular, cells are most con- 

 centrated at the anterolateral and posterolateral margins of the 

 sting, where they are sometimes clumped two or three cells deep 

 within the epidermal layer. The spines of some species are also 

 equipped with a series of sharp, recurved teeth which are capable 

 of producing a severe laceration of the victim's flesh, thus facilitat- 

 ing absorption of the venom and subsequent secondary infection 

 (Fig. 40). The spines of the catfish are particularly dangerous 

 because they can be locked into the extended position at the will 

 of the fish. 



Medical Aspects. The pain is generally described as an instan- 



