688 



TELEOSTEI 



aberrant group. The strongly compressed body is covered with 

 minute, rudimentary scales; the dorsal is short, with few, 

 graduated spines, and the anal much elongate, with 2 small 

 spines ; the ventrals are formed of 1 spine and 5 soft rays. 

 The vertebral column consists of 24 vertebrae; the ribs of 

 the third and fourth are free and slender, whilst the following 



Fig. 419. — Skeleton of Ewrtus indicus. 



are immovably fixed between rings formed by the ossification 

 of the outer membrane of the elongate air-bladder in a manner 

 unique among fishes. The skull is peculiar for its very strong, 

 denticulate, occipital crest, which ends posteriorly in a curved 

 spine bent forwards ; the suborbitals are slender and do not 

 emit a subocular lamina. Kurtus indicus does not exceed a 

 length of 5 inches. 



Division V. — GOBIIFOEMES. 



No bony stay for the praeoperculum. Basis cranii simple. 

 Spinous dorsal, if present, formed of few, flexible rays. None 

 of the epipleural bones attached to the centra of the vertebrae 

 in the praecaudal fegion. Scapula and coracoid more or less 

 reduced or even vestigial ; pterygials large, 4 or 5 in number, 

 forming together a thin plate which is in contact with or 

 narrowly separated from the clavicle ; one or two of the ptery- 

 gials in contact with the coracoid. Ventral fins thoracic. 



The G-obiidae, which alone constitute this division, are not 

 very remote from the Perciformes, and may have evolved out of 

 a type not very different from the Percidae. 



