562 TELEOSTEI CHAP. 



between the inner surface of the quadrate and a descending 

 process of the hyomandibular. Basis cranii double. Ribs very 

 slender, sessile, very low down on the centra ; no parapophyses ; 

 epipleurals and epineurals. Pectorals inserted very low down. 

 Post-temporal forked ; postclavicle absent ; a thin bony lamina, 

 similar to the postclavicle, above the pectoral fin, attached to 

 the scapula ; scapular foramen in scapula ; coracoids in contact 

 with each other, forming a keel. Ventrals very small, with 7 

 rays. Brachiostegal rays 8. Air-bladder large, not communi- 

 cating with the ear, incompletely divided into cells. Mucous 

 membrane of the intestine forming a spiral fold. 



The body is very elongate and strongly compressed, covered 

 with thin, deciduous scales; the vertebrae number 75. The 

 dorsal fin is short and opposite to the anal, which is long. 



FIG. 340. Side view of skull and pectoral arch of Chirocentrus dordb. 



Chirocentrus dorab, the only representative of this family, 

 inhabits the Indian Ocean and the seas of China and Japan. 



Fam. 16. Clupeidae. Margin of the upper jaw formed by 

 the praemaxillaries and the maxillaries. Supraoccipital separat- 

 ing the small parietals ; opercular bones well developed. Basis 

 cranii double. Ribs mostly sessile, inserted behind parapophyses ; 

 intermuscular bones (epineurals, epipleurals, adpleurals) usually 

 numerous. Post-temporal forked, the upper branch attached to 

 the epiotic, the lower to the opisthotic ; post-clavicle applied to 

 outer side of clavicle. Ventrals with 6 to 1 1 rays. Air-bladder 

 large, communicating with the ear. 



Four sub-families : 



(i.) THRISSOPATRINAE. Mouth large ; praemaxillaries very 

 small ; maxillaries large, with rather narrow supplemental bone, 

 firmly attached to praemaxillaries ; branchiostegals about 30 ; 

 abdomen compressed to an edge, without serration ; no lateral 

 line. Thrissopater, from the Gault of Folkestone. 



