464 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.50. 



laries. Thus Girard ^ had in mind as the type of his genus Basil- 

 icJithys what was in reaUty a Menidia. This does not, however, 

 change the type, it remaining the species Atherina microlepidota 

 Jenyns according to a recent opinion of the International Commission 

 on Zoological Nomenclature.^ 



The type of Basiliclithys {microlejndotus) was compared with that 

 of AtJierinopsis, and found to differ somewhat but not genericaUy. 

 Tlie direction of imbrication of the scales on the head is reversed in 

 the former and the vertebrae are more numerous. 



In the following notes the figures in parentheses represent the 

 respective measurements of 15 specimens given in hundredths of 

 body length to base of caudal: 



Head 4^ to 5 in length to base of caudal (0.20 to 0.24) ; depth of 

 body 6 (0.17 to 0.21); eye 5^ in head (0.03 to 0.04); snout 3 (0.07 to 

 0.075) ; pectoral H (0-13 to 0.14); interorbital width 3 (0.07 to 0.08); 

 space between dorsal insertions If to 2 in head (0.11 to 0.14) ; length 

 of gill rakers half diameter of eye; dorsal rays V. (or VI), I, 10 or 11 ; 

 anal rays I, 14 to 16; scales in lateral series 99 to 100; in transverse 

 series between insertions of dorsal and anal fins 24 ; giU rakers 6 + 24 

 (to 27). 



Jaws equal; premaxillaries nonpro tractile, their skm continuous 

 with that of dorsal surface of head ; vomerine teeth present anteriorly 

 in a small patch. 



First dorsal small, mserted midway in the total length; interdorsal 

 space very smaU; dorsal and anal high anteriorly, emarginate; anal 

 terminating before last rays of dorsal; ventrals midway between 

 pectoral and anal bases. 



Scales small, cycloid, subquadrangular; circuli well defined and 

 close set, 5 or 6 basal radii present; no apical radii, those in anterior 

 portion of body about as long as wide, those posterior longer than 

 wide. The direction of imbrication on the dorsal surface of the head 

 reversed in direction. 



Lateral band covers five scale rows, equaling in width the eye, and 

 is without the brightness of that on other Atherinoids, being a dull 

 tarnished silvery. 



It may be noted that this extends the range of this species at least 

 as far south as Conception. The Basilichthys microlepidota of Ever- 

 man and KendaU ^ from Argentina is not this species, having scales 

 larger, 70 to 76 in lateral series. There is no ground as yet for con- 

 sidering the species common to both coasts, or as being found in the 

 Straits of Magellan, 



1 U. S. Naval and Astron. Exped., 1895, p. 238, pi. 30, figs. 8, 9. 



2 Smithsonian Institution, Publication 1938, July, 1910, Opinion 14, in the case of the genus Etheostoma 

 vs. Catonotus and Diplesion. 



» Proc. U. S. Nat. Mus., vol. 31, p. 97. 



