548 



TELEOSTEI 



Pectorals low down, folding like the ventrals. Post-temporal 

 trifid, the upper branch attached to the epiotic, the median to the 

 sc[uamosal, the lower to the opisthotic ; post-clavicle large (formed 

 of three pieces) ; scapular foramen between scapula and clavicle ; 

 pterygials well developed, two in contact with coracoid. Ventrals 

 with 10 to 14 rays. Branchiostegal rays 6 to 14. Air-bladder 

 large, not communicating with the ear. 



Elongate fusiform Fishes, covered with large silvery scales 

 forming regular longitudinal series ; head naked ; mouth rather 

 small, with thick lips ; gill-openings wide. Dorsal fin originating 

 in front of ventrals ; anal short ; caudal well developed, forked. 



Fig. 327. — Albula conorhynchus. ^ nat. size. 



The type of this family, Albula or Butirinus, is remarkable 

 among Teleosts in possessing a rudiment of a conus arteriosus to 

 the heart, provided with two rows of valvules.^ Its single species 

 inhabits all the warm and tropical seas. Prof Gilbert has 

 ascertained that the young pass through a metamorphosis, 

 analogous to that of the Eels. The " Leptocephalid " described 

 as Esmiculus by Kaup is probably a larval Albula. 



Fig. 328. — Larva of Albula conorhynchus. (After Gilbert.) 



The deep-sea Japanese Pterothrissus {Bathythrissa) must be 

 placed in this family; its skeleton is very similar to that of 

 Albula. It differs in the elongate dorsal fin, in the presence 

 of small teeth on the maxillary bone, and in the small number 

 of branchiostegal rays (6 instead of 12 to 14). 



1 Cf. Boas, Morph. Jahrh. vi. 1880, p. 527, who has found the conus, but in a 

 still more rudimentary condition, and with a single row of valvules, ia Heterotis 

 and NotO]>terus also. 



