• STRIATA 



* GEORGEI 

 O STEWARTI 



160 



STANDARD LENGTH IN MM. 



Figure 8. — Regressions of body depth (mm.) on standard length (mm.) for three closely related species 



of Argentina. See,text for equations. 



length. Preanal 83.5 (80.8-85.9) ; preventral 55.5 

 (52.2-58.0) ; predorsal 46.6 (44.2-48.6) ; head 

 length 30.1 (26.1-32.0) ; snout 9.6 (8.5-10.6) ; eye 

 9.8 (7.8-10.9) ; maxillary length 5.4 (4.2-6.1) ; 

 depth at dorsal fin 12.3 (9.7-15.7) ; depth caudal 

 peduncle 5.8 (5.2-6.5). 



Description 



Body not very elongate. Greatest depth at dorsal 

 origin, tapering to caudal peduncle. Figure 8 

 shows a regi'ession of body depth on standard 

 length (Y = .150X — 3.50) compared with two 

 closely related species. The caudal peduncle is also 

 relatively deep. Figui'e 9 shows a regression of 

 caudal peduncle depth on head length (Y=.180X 

 + .524) compared with two closely related species. 

 Body in cross section deeper than wide, dorsum 

 and venter broadly rounded. The head, when 

 viewed laterally, has its dorsal profile barely if at 

 all broken by the upper margin of the eye; the 

 ventral profile rises to the snout in a gentle curve ; 



many specimens are preserved with the mouth 

 open and the basibranchial projecting into the 

 ventral profile. The interorbital space between the 

 supraocular canals is flat or only slightly concave. 

 The dorsal portion of the maxillary lies under the 

 lachi-ymal. The distal end of the maxillary is 

 usually about midway between the tip of the snout 

 and the anterior margin of the eye. The jaws are 

 broadly rounded, the lower slightly included. The 

 palatine and the head of the vomer bear small, 

 closely spaced, needlelike teeth in a continuous 

 band from 2 to 5 teeth wide, about 30 on the vomer 

 and 40 on each palatine; dentary teeth are lacking. 

 The ceratobranchial of the fifth gill arch bears 9 

 small, conical teeth ; two patches of similar teeth, 

 10 on the anterior patch and 14 on the posterior 

 patch are at the anterior end of the fourth supra- 

 branchial ; there are also a few teeth on the tliird 

 suprabranchial. The tongue bears eight strong re- 

 curved teeth (description of dentition based on a 



ADDITIONS TO A REVISIOX OF ARGENTININE FISHES 



23 



