FISHES OF THE PHILIPPINE ISLANDS AND ADJACENT SEAS 733 



says the youngest example he has seen measures 75 mm. and is 

 extraordinarily slender, and he gives the depth for the young as 

 111/2. 



A.N.S.P. 53065. Natal coast, in 60 fathoms. 1924. H. W. Bell Marley. Length, 

 100 mm. 



Series OSTARIOPHYSI 



Front or anterior vertebrae modified, interlocked, enlarged, coossi- 

 fied and some with their upper and lateral portions detached to 

 form a series of small bones or weberian ossicles, connecting the 

 auditory apparatus with the air bladder. The air bladder thus 

 apparently an organ of hearing by means of a connection which 

 lost in all higher fishes. 



This great group includes the majority of all freshwater fishes. 

 But two of the four orders are here considered, as I report only the 

 few Philippine cyprinoids and siluroids. The latter include also the 

 marine forms. The numerous East Indian species are well treated 

 in the great works of Bleeker and in more recent years by Weber 

 and Beaufort. The forms of more remote relationship such as those 

 in the Indian region and the quite distinct fauna of the Cliinese 

 mainland are omitted because they are not represented in the Alba- 

 tross Philippine collections. 



Order Nematognathi 



Body variously short to greatly elongate or even eellike. Head 

 very variable, sometimes extremely large, wide or depressed, again 

 very small. Mouth not protractile, premaxillaries usually forming 

 its upper borders. Lips sometimes greatly developed, sometimes 

 modified as sucking disk. Mouth with long barbels, usually at least 

 one pair from rudimentary maxillaries, often one or more pairs 

 about chin and sometimes one from each pair of nostrils. Subopercle 

 absent or modified as uppermost branchiostegal. Four front verte- 

 brae joined together, with chain of small bones as weberian appar- 

 atus to auditory organ of skull. Skin thick, slimy, or with bony 

 plates on head and about pectoral fins. No true scales ever present. 

 Adipose fin frequently present. Usually teeth on jaws, vomer and 

 pterygoids. Pharyngeal bones with small conic or villiform teeth. 

 Branchiostegals 4 to 17. No pseudobranchiae. Intestinal canal 

 simple, short to elongate. No pyloric coeca. Lateral line usually 

 present, sometimes with branches. Fin rays articulated, second 

 dorsal ray and outer pectoral ray modified as spine due to co-ossifica- 

 tion of articulations. Pectorals placed low, fold like ventrals. 

 Ventral rays 6 to 16, frequently about 6. 



