Fishes of the Western North Atlantic 259 



Head depth: distance from a slight crossgroove at the occiput, between the 

 naked head and scaly body, to margin of first ventral scute; this line may be vertical 

 or may slope somewhat backward from the occipital crossgroove. 



Snout: distance from anterior margin of snout to anterior margin of orbit. 



Eye: horizontal diameter of eyeball, not of orbit. 



Maxillary: distance from anterior rim of snout to maxillary's posterior margin. 



Mandible: distance from its tip to its joint. 



Interorbital: width of bone over or between middle of eyes. 



Cheek: the bone, usually with a glossy surface in the herrings, lying below and 

 usually somewhat behind the eye, its depth measured from lower rim of orbit to its 

 lowest or deepest point. 



Predorsal length : distance between anterior margin of snout and origin of 

 dorsal. 



Caudal lobes: distance from midbase of this fin to tip of lobe. 



Pelvic and Pectoral fins: distance from base of outer or upper ray to tip of fin. 



Fin ray count: includes all rays, whether rudimentary, simple, or branched; 

 the last ray, even though nearly double, counted as one. 



Scales: range in scale numbers, e.g. 56-62, obtained by counting the oblique 

 rows (upward and slightly forward) that cross the side between upper anterior angle 

 of gill opening and base of caudal; any deviation from that procedure is stated. 



Gill rakers: number present on first gill arch, including rudiments if present; 

 all enumerations based on adult fish unless stated otherwise. 



Ventral scutes: three sets of counts are given: the range of the total number 

 present, the number in front of the pelvic fins, and the number behind these fins; the 

 scute ending nearest to the insertion of the pelvics is included in the number in 

 advance of these fins; the rest compose the number behind. 



Vertebrae: total number, including the hypural. 



Key to Western North Atlantic Subfamilies and Genera of Clupeidae^ 



I a. Body little compressed; abdomen rounded, covered with ordinary scales, without 

 bony scutes. Subfamily Dussumierinae. 



Atlantic coast of North America; 

 eastern and western Pacific; south- 

 eastern coasts of Africa and Australia. 

 2 a. Pelvic fin much smaller than pectoral, inserted behind base of dorsal; dorsal 

 fin with about 17-20 rays; chest round. Etrumeus Bleeker 1853, p. 262. 



2b. Pelvic fin nearly as large as pectoral, inserted under base of dorsal; dorsal 

 fin with only about 9-14 rays; chest slightly keeled. 



Jenkinsia Jordan and Evermann 1896, p. 267. 



3. This Key is drawn up^simply for the ready identification of representatives of the subfamilies and genera that are 

 known from the western North Atlantic without reference to those outside of this range. Therefore, some characters 

 are used that apply only to the representatives described in this work and for that reason are not of generic value. 



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