288 ZOOLOGY. 



4°. Atherina macropMhalma Agass.,* A. brasilensis, Ouv. and Val.; from the bay of Rio 

 de Janeiro. 



5". Atherina honariensis , Guv. and Val., from Buenos Ayres. 



6°. Atherina lichtensteinii, Cuv. and Val., from Montevideo. 



And, in all probability: Atherina regia, HuMB.,t from Peru, and Atherina lessonii, Cuv. 

 and Val., from Brazil. 



The genus Heterognatuus is based upon the elongation of the lower jaw, which projects 

 considerably beyond the upper one. No teeth on the j^alate, or else in a rudimentary state only. 



Atherina humboldtiana and A. vomeriana, Cuv. and Val., both from Mexico : whether from the 

 fresh or salt waters, it is not stated. 



In all Atherinopsis, Basilichthys, and Meterognathus, the intermaxillaries constitute the upper 

 arcade of the mouth at the exclusion of the maxillaries, which are situated behind the latter. 

 This character will distinguish them at once from Atherina proper. 



Genus BASILICHTHYS, Qirard. 



GrEN. CHAR. IntermaxiUaries constituting the upper part of the mouth, the maxillaries 

 being placed behind. Head and snout subcorneal; upper jaw protruding beyond the lower. 

 Small teeth on both jaws; none on either the vomer or palatines. Upper surface of the head 

 scaly. 



Stn. Basilichthys, Grd., Pro. Acad. Nat. Sc. Philad. VII, 1854, 198. 



Obs. Like Atherinopsis, the present genus includes species of its family which are unprovided 

 with teeth of any kind on the upper roof of the mouth. The mouth itself has the same general 

 structure as regards the disposition of the intermaxillaries and maxillaries, but the conical 

 shajje of the head, and the protrusion of the upper jaw beyond the lower, will constitute the 

 generic feature of Basilichthys. 



BASILICHTHYS MICEOLEPID OTUS, Girard. 

 Plate XXX, Figs. 6—9. 



Spec. char. Upper surface of head depressed and subconvex. Cheeks and upper portion of 

 opercle covered with conspicuous scales. Origin of anal considerably in advance of anterior 

 margin of second dorsal. First dorsal opposite the middle of space between anals and ventrals. 

 Caudal forked. Ground-color yellowish brown, dotted with blackish ; a silvery grey band along 

 the middle of the flanks. 



Syn. Atherina microlepidota, Jen. Zool. of Beagle, IV, Fish. 1842, 78, PL xvi, fig. 1, la, 16. 

 GuicH. in Gay, Hist, de Chile, Zool. II, 1848, 253. 

 Basilichthys microlepidotus, Grd. Acad Nat. Sc. Philad. VII, 1854, 198. 

 Feje rey, vernacular. 



Descr. The general form is elongated, subfusiform, and slender; the back being rounded, 

 whilst the flanks diminish considerably in thickness from the silvery band towards the medial 

 line of the belly. The greatest dejith of the body, measured above the insertion of the ventral 



' Pise. Brazil, 18^7, PI. ilvu. Fig. 1. 



t Rec. d'Obs. do Zool. et d'Anat. Couij;. I, Ib'io. 



