344 



Memoir Sears Foundation for Marine Research 



be counted uniformly, since they tend to become reduced in size on the back and 

 larger on the lower part of the side. The comparisons and figures given on these pages 

 are based on scales from the middle of the side below the anterior dorsal rays. 



Caudal fin: lower lobe measured from middle of caudal base. 



Pectoral fin: axillary appendage measured from base of upper pectoral ray. 



Figure 84. Brevoortta pelvic fins: a, patronus, 215 mm TL, off Galveston, Texas, USNM 1298 10, see Fig. 

 91 ; B, tyrannus, 320 mm TL, Chesapeake Bay, USNM 129809, see Fig. 86; c, gunteri, 270 mm TL, Rock- 

 port, Texas, USNM 129798, see Fig. 93; d, smhhi, 295 mm TL, USNM 1 18723, see Fig. 92; all equally 

 enlarged. Drawn by Ann S. Green. 



Species. Five species fall within the scope of this work (see Key to Species), and 

 two others, aurea iLud pectinata, occur in southern Brazil, Uruguay, and Argentina. Still 

 another one, sometimes identified with tyrannus, has been reported for western Africa. 

 I have seen no specimens of the latter and cannot add any information as regards its 

 relationship to American forms. In general, the scales of South American representa- 

 tives are scarcely reduced in size on the back and on the base of caudal, whereas in 

 North American species they are greatly reduced there. 



Key to Species of the Western Atlantic 



I a. Scales fairly regularly placed, 35-36 oblique series crossing middle of side; great- 

 est depth of body 30-40 "/o of SL. 

 2 a. Scales on back and at base of caudal much smaller than those along middle 



