﻿404 PROCEEDINGS OF THE NATIONAL MUSEUM vol. lOO 



ever, indicate very close agreement between smithi and cepedianum, 

 as shown by the following data (range, followed by mean in paren- 

 theses) : 



Measurement cepedianum anale chavesi smithi 



Mandible, length 87-116 (99) 82-99 (88) 110-165 (128) 90-104 (96) 



Upper jaw, length 71-90 (80) 61-76 (69) 91-130 (106) 72-89 (79) 



The data for cepedianum are based on 20 specimens from Maryland 

 and the Great Lakes region southward and westward to Texas; 

 these specimens varied in standard length from 83 to 153 mm., with 

 a mean of 118 mm. Measurements for the other species are taken 

 from table 5. 



In discussing the variant series of three specimens from Rio Muerto, 

 Sonora, Hubbs and Miller (1941, pp. 237-238) pointed out certain 

 characteristics by which these specimens differed from the five then 

 known from Sinaloa. It was thought that the Sonoran individuals 

 might possibly represent a distinct subspecies. In the number of anal 

 rays they still show a lower average value, but the gap between their 

 counts and those of the five types from Rio Piaxtla has been com- 

 pletely bridged by the new material (table 9). The total number of 

 ventral scutes, 27 to 29, contrasts with that of 26 to 27 ^ for the types 

 but again is overlapped by counts of 26 to 30 (usually 27 to 28) for 

 specimens from the intervening regions. The measurements by which 

 variants and the types differ are now largely bridged over by those 

 of the new material (table 8). In the few measurements that still 

 distinguish the northern stock from the rest, such as the shorter and 

 narrower head and the smaller snout and eye, the differences may 

 well be the result of emaciation. A good series from the basin of the 

 Rio Yaqui, Sonora, should clarify this interpretation. 



The caudal rays of 94 specimens were 19 except for two with 18 

 and one with 17 rays. Counts of 147 pelvic fins gave the following 

 results: 7-6 (1), 7-7 (15), 7-8 (16), 8-7 (15), and 8-8 (100). Thus, 

 although each pelvic fin of D. smithi usually has 8 rays, there is con- 

 siderably more variation in this count than there is in the other 

 species of Dorosoma. 



Material examined. — A total of 185 specimens, all from Mexico, 

 were examined as follows: 



U. M. M. Z. Nos. 133749-50; Holotype and 4 paratypes, 46 to 123 mm. long^ 

 from Rfo Piaxtla near Piaxtla, Sinaloa. 



U. M. M. Z. No. 133751: 3 adults, 104 to 126 mm. long, from Rio Muerto, a 

 coastal distributary of Rio Yaqui, about 46 road miles south of Guaymas, Sonora. 



U. S. N. M. No. 129952: 52 young to adults, 52 to 122 mm. long, from Rfo del 

 Fuerte, 0.5 mile from San Bias, Sinaloa. 



8 In the original description the holotype was recorded as having 28 ventral scutes. Reexamination shows 

 that only 27 are present. 



