Suborder Elopoidea 



COMPOSITE AUTHORSHIP 



Characters and Key to Families 



HENRY B. BIGELOW2 



Museum of Comparative Zoology 

 Harvard University 



Characters. Silvery, herring-like isospondylous fishes with the Parasphenoid 

 BONE on posterior part of roof of mouth thickly set with low Teeth,' extending 

 nearly to posterior end of basioccipital or beyond, without lateral processes for articula- 

 tion with the mesopterygoid. Temporal foramina present. Parapophyses not fused 

 with vertebral centra, but simply wedged in pits. Proethmoids not paired (see Eso- 

 coidea. Part 4). Pectoral girdle with mesocoracoid element. A Bony (gular) plate in 

 chin region between branches of lower jaw in some (Elopidae, including the Megalo- 

 pidae of Matsubara) but not in others (Albulidae, Pterothrissidae). Luminescent 

 organs absent. Adipose fin lacking between rayed dorsal and caudal. Pelvic fins 

 abdominal, standing from about 3070 to about 45 "/o of distance rearward from gill slit 

 toward lower origin of caudal. Anal fin originating from about 50 "/o to about 68 "/o of 

 distance between pelvics and caudal. Caudal deeply forked. Rearmost dorsal ray 

 greatly prolonged in some (Tarpon, Megalops); the Rearmost anal ray prolonged as 

 well in a few (Dixonina); none of the other fin rays prolonged. A single large, nar- 

 row, fleshy Axillary scale above pectorals and pelvics. Scales thin, cycloid. Eyes 

 circular, of the ordinary type. Upper jaw extending rearward far beyond eye in most, 



1. With families Elopidae and Albulidae by Samuel F. Hildebrand, pp. in and 132, respectively. 



2. The assistance of Dr. W. A. Gosline is gratefully acknowledged. 



3. Ridewood, who described their skulls in detail, has recorded this peculiar dentition (j: 39, for Elops; 44, for Mega- 

 lops; 40, for Albula; 53, for Pterothrissus). These observations have been verified for Plerothrissus by Poll [2: 222, 

 fig. 7), and for Tarpon by original examination. 



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