﻿REVIEW OF GENUS DOROSOMA — MILLER 



393 



Since 21 counts of the caudal rays were invariably 19, and 23 counts 

 of the pelvic rays were 8-8 (with two exceptions, both 7-8), no further 

 examination of these fins was made. As shown below, 19 caudal and 

 8 pelvic rays predominate in Dorosoma, and therefore counts of these 

 fins are of no systematic value for distinguishing the species of this 

 genus. 



The possibility that examples of the southernmost populations of 

 D. cepedianum. from Mexico might more closely approach its nearest 

 representative, D. anale, was dispelled by an examination of four 

 specimens of cepedianum from the Rio Pdnuco Basin, Mexico, just to 

 the north of the range of anale. Two of these fish were from Rio 

 Valles at Valles, San Luis PotosI (C.N.H.M. No. 4497); one was 

 from Rio Forion at Forl6n, Tamaulipas (C.N.H.M. No. 4481); and 

 the fourth was from Rio San Juan at San Juan del Rio, Queretaro 

 (S.N.H.M. No. 31996). All were recorded by Meek (1904, p. 94) 

 as D. exile. The following critical counts on these specimens are 

 typical of cepedianum: Lateral scales, 58, GO, 65?, 58; scales from 

 dorsal to anal, 22, 23, 21, 20; scales around body, 41, 40, 41?, 40; 

 scales around peduncle, 16, 18, missing, 16; ventral scutes, 18+12, 

 17+12, 18+12, 17+11; vertebrae 50 (Forl6n specimen). 



Table 3. — Number of scales in four species of Dorosoma 



[The figures in the first line for each count arc the observed range and, in parentheses, the mean; the figure 

 in the second hne represents the number of specimens] 



The apparent uniformity in the meristic characters of cepedianum 

 over such a vast range should not be accepted on the basis of the 

 present data but should be thoroughly tested. No doubt Regan 

 (1917, p. 311) correctly assigned Meek's material (identified as D. 

 exile) to cepedianum, but whether exile is a valid subspecies of cepedi- 

 anum has not been determined conclusively.* Fowler (1945, pp. 22, 

 365-366), presenting data on body depth only for scanty material from 



' I have been unable to locate the types (tv.o specimens) of D. c. exile Jordan and Gilbert (1882, p. 248; 

 1883, p. 585), which bear U.S.N.M. No. 30913. The catalog book records that they were "Distributed," 

 that is, sent out to some institution. 



