6 CHONDROFTEBYGII. SELACIIOIDEI. 



peidce are very capricious, sometimes forsaking the coast for several 

 successive years, and then as suddenly reappearing in countless 

 millions (see Clupea lonyiceps). No livers under 40 Ib. weight 

 were accepted at the factory, as the larger ones gave propor- 

 tionally a greater amount of oil than the smaller ones ; sometimes 

 li vers of a great size were purchased. One weighed 290 Ib., and 

 another from a female saw-fish 14 feet long 185 Tb. 



The division Selachoidei among the Plagiostomata has been 

 further subdivided into nine families, the following only of which 

 have as yet been recorded from the seas of India : 



I. A nictitating membrane to eye ; two dorsals and 



an anal fin Carchariidae. 



IT. No nictitating membrane to eye ; two dorsals and 

 an anal fin; nostrils not confluent with mouth, 

 which last is inferior. Spiracles absent or minute . Lamnidae. 



III. No nictitating membrane to eye ; two dorsals nnd 

 an anal fin. Mouth near the extremity of the 



snout. Teeth small and conical Rhinodontidae. 



IV. No nictitating membrane to eye ; only one dorsal 



and an anal fin Notidanida?. 



V. No nictitating membrane to eye ; two dorsals and 

 au anal fin. Mouth inferior. Teeth small, several 

 rows being generally in use at the same time .... Scylliidae. 



Family I. CAECHARIID^E. 



The snout may be produced longitudinally or laterally. Spiracles 

 absent or present. Eye with a nictitating membrane. A small 

 pit may or may not exist above the root of the tail, and a groove 

 at the angle of the mouth may be present or absent. Mouth 

 crescentic, inferior. The teeth may be erect or oblique, with a single 

 cusp, having smooth or serrated edges ; or they may be small, 

 the cusps being obsolete ; or with one central and one or two 

 lateral cusps. The first dorsal fin, destitute of a spine, is placed 

 opposite the interspace between the pectoral and ventral; anal 

 fin present. 



The most abundant species of this family along the coasts of 

 India undoubtedly are such as belong to the genus CarcJiaricw, 

 the immature of which are very destructive to herrings and other 

 edible fishes. It has been observed that one of the remarkable 

 results which has followed the construction of the Suez Canal has 

 been the introduction into the Mediterranean sea of sharks, which 

 were formerly almost unknown there. 



The number of species of this family found in the Red Sea by 

 Klunxinger, as recorded in his ' Synopsis der Fische des Rothen 

 Meeres' in 1871, was as follows : Carcharias 6, Loxodon 1, Galeo- 

 cerdo 2, Dirrhizodon 1, which does not show that these fishes are a 

 large element in the fish-fauna. As, however, the more open Indian 

 Ocean is reached, the number of these destructive fishes largely 



