422 BULLETIN 189, UNITED STATES NATIONAL MUSEUM 



The following proportions and enumerations are based on eight 

 specimens 56 to 115 mm. (44 to 90 mm. to base of caudal) long, from 

 La Lagunilla, which definitely have bands of teeth on both jaws: 

 Head in length 3.1 to 3.35; depth 3.39 to 3.4; base of anal 7.2 to 9.0; 

 pectoral 5.1 to 5.9. Eye in head 4.0 to 4.8; snout 4.2 to 5.0; maxillary 

 4.2 to 5.0; interorbital 3.0 to 3.6; caudal peduncle 2.9 to 3.5; anal base 

 2.2 to 2.8; pectoral 1.6 to 1.8; D. IV-I, 8; A. Ill, 8; P. 16; scales 40 to 

 44; vertebrae 23 or 24 (3 specimens dissected) ; gill rakers 31 in a speci- 

 men 56 mm. long, 37 in one 86 mm. long, and 42 in another one 110 

 mm. long (60 in a specimen 240 mm. long), evidently increasing in 

 number with age. 



The specimens herein identified as M. rammelsbergii differ from those 

 identified as M. cephalus chiefly in having a broad band of teeth in each 

 jaw instead of having the teeth chiefly in a single row; the lower jaw is 

 rather thicker and the inner surface is convex instead of flat; and the 

 mouth is wider, the maxillary measured in a straight line from a 

 median point on snout to its extremity being shorter than width of 

 mouth at its angles, whereas in M. cephalus it is about equal to the 

 width of the mouth. The difference in the width of the mouth, 

 although quite evident in the large examples at hand, becomes obscure 

 in the smaller ones. Then, as stated elsewhere, several small specimens 

 I am unable to place with certainty in either species. It seems 

 possible, therefore, that intergradation occurs. However, I have 

 examined quite a number of specimens of M. cephalus of various sizes 

 from other American localities, especially Chesapeake Bay and Beau- 

 fort, N. C, without finding any with a band of teeth on the lower jaw. 



The chief reason for using the name rammelsbergii, which has long 

 rested in the synonymy of M. cephalus, is the statement in the original 

 description, "Die Zahne sehr zalreich, aber fein," The teeth, although 

 fine in M. cephalus, can scarcely be defined as "very numerous." 



Range. — Coast of Peru and nearby islands. To date known only 

 from latitude 6°56' to 14°13' S. 



MUGIL CEPHALUS Linnaeus 



Liza 



Mugil cephalus Linnaeus, 1758, p. 316, Europe (diagnosis, based on Artedi, 

 pre-Linnean) . — Abbott, 1899, p. 343, Callao, Peru (notes; description of 

 M. rammelsbergii Tschudi quoted in full. M. rammelsbergii herein is recog- 

 nized as distinct from M. cephalus). — Regan, 1913, p. 279, Pacasmayo, 

 Peru. — EvERMANN and Radcliffe (in part not of Linnaeus), 1917, p. 49, 

 Callao, Ancon, Arequipa (market), Rio de Eten (near Eten), Rfo Rimac 

 (below Lima), and Pacasmayo, Peru (description; locally abundant). — 

 Nichols and Mubphy, 1922, p. 506, south of Paracas Peninsula, Peru. — 

 Meek and Hildebrand, 1923, p. 275 (synonymy; description; range). 



tQuerimana harengus Regan, 1913, p. 279, Pacasmayo, Peru (young). 



