522 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY IV. 
(with caudal). D. X, 10; A. 8. L. inches. Eio Seco and Eio Leona, 
Texas. {Girard.) The types of this species, examined by us, have the 
lateral line incomplete and the premaxillaries not protractile. 
[Bolcosoina gracile Girard, Proc. Acad. Nat. Sci. Pliila. 1859, 103.) 
** Dorsal spines G; anal spines obsolete? {Alvariun^ Girard.) 
823. P. flateraHas (Grd.) J. & G. 
“ A representative of the Etheostomoid family was procured by the 
United States and Mexican Boundary Commission at the Eio Grande 
del Xorte (Eio Bravo). It constitutes a new generic type allied to 
Catoiiotus, and to which we have applied the name of Alvarius, with the 
following characters. Head elongated and tapering. Mouth terminal, 
large, not protractile; lower jaw longer than the upper. Teeth very 
minute. Opercular apparatus, cheeks, and throat scaly. First dorsal 
nearly equal in height to the second, from which it is quite distinct. 
Anal tin much smaller than the second dorsal ; caudal tiu truncated ; 
five soft rays to the ventrals. Ventral scales uniform.” Body slender, 
elongate. Head subcouical and tapering forward. Eye equal to suout^ 
4 in head. Maxillary reaching pupil. First dorsal about equal to second 
and separated from it. Anal smaller than second dorsal, the last rays 
of the two tins opposite each other. Scales very small. Lateral line 
median. Brownish, back spotted ; sides with a narrow blackish streak, 
which extends around the snout; first dorsal with a black spot on its 
upper posterior edge; caudal transversely barred. 13. VI, 10; A. 8. L. 
If inches. Eio Grande. {Girard.) 
{Alvarius lateralis Girard, Proc. Acad. Nat. Sci. Pbila. 1859, 101.) 
26t.— ]?IICfiS©PEKCA Putnam. 
(Putnam, Bull. Mus. Corap. Zool. I, 1853, 4: type Microperca punctulata Vwin.) 
Body rather short, compressed. Mouth moderate, the jaws about 
equal. Premaxillaries not protractile. Vomerine teeth present. Gill- 
membranes scarcely connected. Scales large. Lateral line obsolete. 
Dorsal fins small, subequal, well separated, the first with six or seven 
spines ; anal fin much smaller than second dorsal, with two well-devel- 
oped spines. Color greenish, with dusky markings. Size very small, 
probably the smallest of the spiny-rayed fishes, {/iczpo^, small; -epxrj, 
perch.) 
824. Tfl, pn’CKlnairas Hay. 
Body short and stout. Snout conical, pointed; jaws equal; mouth 
Girard, Proc. Acad. Nat. Sci. Pbila. 1859, 101: type Alvarius lateralis. (A 
coined name without meaning.) 
