6 BULLETIN OF THE BUREAU OF FISHERIES. 
chiostegals 8. The air bladder is large, thin, and single lobed, extending the whole length of the 
visceral cavity. The peritoneum is somewhat silvery in places, but is without dark pigment. No 
teeth are found. 
Coregonus spilonotus, new species. Bonneville whitefish. 
Gill nets set at a depth of about a hundred feet in Bear Lake in August caught numbers of a spotted 
whitefish which measured from 155 to 200 millimeters in length. They were pale moss-green above, 
silvery on the sides, and white beneath. Spots, dusky in color, round, and somewhat larger than the 
pupil, extend from the occiput to the base of the caudal. These fishes differ from C. williamsoni in 
that the spots are smaller and more numerous, the scales are larger, and the heads longer. They were 
from 4 to 5 years old, and the condition of the ovaries seems to indicate that they were mature indi- 
viduals. 
At the same time and at the same depth large whitefish colored like the above, except that they 
were without spots, were taken on baited hooks. Besides being plain in color, these fish were much 
larger, 400 to 470 millimeters long; the heads were longer, the body deeper, the maxillary larger, and 
they were distinguished also by their general appearance. They were from 7 to 10 years old, and 
mature. 
Coregonus spilonotus. Bonneville whitefish. 
Locally these two forms are regarded as distinct, but a considerable series of specimens collected 
by Mr. Stock supplies examples intermediate in size and age, and seems to demonstrate without much 
doubt that they belong to the same species. The question need not be considered as settled, however, 
until more complete data have been obtained. 
This species appears to inhabit the deep water. It is to be found there as late as the month of 
August, and it is in the same region in January and February, when it feeds upon the eggs of other 
whitefish. In December, however, it migrates shoreward and spawns in shallow water. It does not 
enter the rivers. 
Type No. 83499, United States National Museum. Locality, Bear Lake, near Fish Haven, 
Idaho. Length 425 millimeters. Collectors, J. O. Snyder and C. L. Hubbs. 
Head 3.8 in length to base of caudal; depth 3.6; depth caudal peduncle 3.5 in head; snout 2.9; 
eye 4.8; interorbital area 3; maxillary 3.2; scales lateral series 80; between occiput and dorsal 34; 
above lateral line 11; below lateral line 9; dorsal rays 11; anal rr. 
Body deep and rather heavy, the head very large, with a long snout and broad maxillary. Gill 
rakers short, thick, and pointed, 6+-13 on first arch. Fins rounded; caudal small; adipose about equal 
in size to maxillary. Color dusky above, silvery on the sides, white below; no spots. 
The spots disappear with age, the head grows relatively larger, the maxillary longer, and the 
body deeper. The lateral series of scales numbers from 74 to 81; series above lateral line g to 11; 
between occiput and dorsal fin 30 to 37. The dorsal has ro to 12 rays; anal g to rr. 
