FISHES, LAHONTAN SYSTEM OF NEVADA AND NORTHEASTERN CALIFORNIA. 67 



and with it, in the dim light of the early morning, myriads of fishes from the depths of the lake. Daylight 

 revealed them everywhere, along the shore, among the bowlders, and in the algse, hovering in enormous 

 schools over the bars and moving about in the clear water of the sheltered bays. From this time the 

 suckers rapidly disappeared, while the large trout approached the shore in their eagerness to feed on 

 the luckless minnows. 



Most of the fishes engaged Ln this particular migration were L. pectinifer, although many examples 

 of S. obesus were seen among them. At this time the latter were often taken in deep water with a troll 

 at some distance from shore. Most of these fish (L. pectinifer) were not ready to spawn, and no ripe 

 individuals were seen until May 24, after which date spawning soon began. 



Residents report that during the summer large numbers of minnows frequent the inshore waters, 

 but that in September they disappear and are seen no more until the following spring. Late in the 

 siunmer great numbers of small minnows swarm in the shallows near shore. Young specimens of this 

 species were taken from several schools in protected, shallow bays in Winnemucca Lake, June 17, 1913. 

 They were of two distinct sizes, measuring, respectively, 42 to 58 and 65 to 80 millimeters. There 

 was a black lateral stripe extending along the side, broader, darker, and more definite in outline pos- 

 teriorly and enlarging greatly near base of caudal fin, where there is a more or less distinct dark spot. 

 The scales of the lateral line are very thin, the tube is large, and when the scales are rubbed off the 

 line appears broken or incomplete. 



Large numbers of the species fall a prey to gulls, cormorants, and pelicans, the latter scooping 

 them up in great numbers to feed their young. They contribute largely to the food of the trout. They 

 make excellent pan fishes, although very bony. 



The species appears to be entirely lacustrine. 



Agosia robusta Rutter. Black minnow. 



The name robusta was first applied by the describer of this species" to examples of Agosia found 

 in tributaries of the Truckee and Susan Rivers. It was later ^ used to include fishes of the genus 

 found in streams of the western slopes of the Sierras which flow into the Sacramento and San Joaquin 

 Rivers. It was at first thought to be characterized by the blunt, rotmded snout, the heavy body, 

 incomplete lateral line, absence of scattered brown scales, shorter pectorals, greater development of 

 rudimentary caudal rays, scales in lateral series 56 to 57, and in the presence of a silvery stripe across 

 the cheek. Later it was seen to be "quite variable," and, in the hands of its describer, it was assum- 

 ing the same complex medley of variations which are found in A. carringtoni or A. ntibila carringtoni 

 of later \vriters. It now appears that the name must be restricted to the Agosia of the Lahontan system 

 or else abandoned entirely, for if its range is extended to include even a part of the Sacramento system 

 its variation becomes so great that it can not now be differentiated from the form or forms occupying 

 the Oregon Lake region or the upper Gjlumbia. As yet the present vmter is unable to find any char- 

 acter or set of characters which will distinguish Agosia robusta, and the name is therefore only pro- 

 visionally retained. 



A large series of specimens from the Lahontan system are at hand, and from these the following 

 observations are made ; 



The snout is short and evenly rounded from its tip to the interorbital space. It is not blunt, nor 

 does it project much beyond the mouth in any case. The under jaw is included. The maxillary is 

 protractile, no frenmn appearing. Barbels are present on both sides, on one side only, or absent alto- 

 gether. When present, they are occasionally long and prominent, but at times they are so short as to 

 almost escape notice. When one only is present, it is indifferently on the right or left side. 



a Bulletin, United States Fish Comjnission, vol. xxn. 1902, p. 148. 

 ^ Bulletin, United States Bureau Fisheries, vol. xxvni, 1907, p. 139. 



