116 ZOOLOGY OF THE VOYAGE OF THE BEAGLE. 
at Maldonado, in a lake that had been suddenly drained. There are three spe- 
cimens in the collection, none of them exceeding the length above given. Mr. 
Darwin, however, states in his notes, that he believes them to be full grown, 
having taken them so repeatedly, in brooks, of the same size. The number of 
spots varies from nine to twelve, and is sometimes different on the two sides of the 
same specimen. 
Independently of the spots, which at once characterize this species, it is 
readily distinguished from the last by its teeth, which are more cutting than point- 
ed, and in this respect rather departing from the character of the genus as esta- 
blished by Valenciennes. 
1. LEBIAS LINEATA. Jen. 
Prate XXII. Fig. 2. 
L. corpore subelongato, subcompresso, viridescenti-fusco ; lateribus lineis circiter 
seplem longitudinalibus nigris, e maculis parvis subconfluentibus formatis : dentibus 
unisertatis : caudali retundata. 
D.9; A. 9; C. 26, brevibus inclusis; P. 13; V. 6. 
Lone. une. 1. lin. 10. 
Form.—General form very similar to that of the Pacilia decem-maculata. Slightly compressed ;_ the 
depth one-fifth of the length; the length of the head about four-and-a-half times in the 
same, Head depressed: snout obtuse: mouth small; the commissure horizontal. Upper jaw 
very protractile ; the lower one rather the longest, when the mouth is shut. Teeth forming 
a single closely-set series, somewhat compressed at bottom, the cutting edges tricuspid. 
Diameter of the eye nearly one-fourth the length of the head. Some large conspicuous pores 
on the lower jaw, passing upwards in a series along the margin of the preopercle, not very 
near together, about eight or nine in all. 
Scales large, covering the head and all the pieces of the gill cover, as well as the body. 
About eight in the depth, and thirty in a longitudinal line from the gill to the caudal. 
One taken from the middle of the side of a semi-elliptic somewhat oblong form; the free 
portion very finely striated, the basal with ten or twelve deeper-cut strie, these last nearly 
parallel, and of equal lengths. Lateral line faintly marked out by a dotted line; the first 
half in the third row of scales from the top, the last half in the fourth row. 
Dorsal commencing at exactly the middle point of the entire length. Anal opposite and 
similar. Caudal rounded. Pectorals small, about two-thirds the length of the head. Ventrals 
smaller, barely one-half of the same. The pectorals, when laid back, reach to the insertion of 
the ventrals; but the latter hardly attain to the anal. 
Corour.—Greenish-brown, with six or seven longitudinal dark lines on the sides, the lines appa- 
rently made up of spots for the most part confluent, but here and there not so, interrupting the 
continuity of the lines. All the fins pale dusky, without any spots or markings. 
Habitat, Maldonado. 
This new species of Ledias was taken by Mr. Darwin in the same lake at 
