224 BULLETIN OF THE BUREAU OF FISHERIES. 



when forced out of the pellicle, proved to be wholly shells of a species of cladoceran, 

 apparently Chydorus. A three-sixteenth-inch piece was cut from the middle of the 

 alimentary canal where it is of average size, and the Crustacea in an estimated fifth of 

 this counted. From this the entire number in the alimentary canal was estimated at 

 about 2,400. Only 2 or 3 copepods were found in the sample, or 48 for the whole 

 alimentary canal; the rest were Cladocera and all of one species. There was no sand, 

 so that it may be safely said that the young sucker is not a bottom feeder, but lives 

 wholly on the plankton. 



The stomachs of 1 2 of the suckers included in the table were examined and found 

 to be empty. In August, 191 2, Prof. Frank vSmith saw the adults feeding on the mate- 

 rials encrusting the vegetation at the mouth of Bessie Creek. They were sucking off 

 whatever adhered to the floating stems and leaves of the plants. They went from 

 plant to plant and mouthed over each branch from base to tip until the whole plant 

 had been gone over. 



The adult suckers may sometimes be seen at dusk or daybreak feeding on the 

 bottom over the sand shoals. When approached they ordinarily make off at once for 

 deep water. On July 3, 191 2, I found several feeding on the sand shoals at midday, 

 and each was surrounded by a group of a dozen or more log perch. The log perch 

 were at that time laying their eggs in the sand and the suckers were feeding on the eggs. 

 Each sucker was surrounded by a group of log perch which were trying to get such 

 scraps as might be left from its feeding. It would be interesting to know whether this 

 commensal relation between sucker and log perch obtains at other seasons and in 

 deeper water. 



While the suckers are thus engaged it is not difficult to approach them until they are 

 at one's feet and to watch closely their method of feeding. The sucker moves slowly 

 over the bottom. At interv^als it stops, raises its tail until, if in very shallow water, the 

 caudal fin breaks the surface. It buries its snout in the sand, often to the nostril, but 

 sometimes onlv half so far. The fish then withdraws its snout from the sand and without 

 moving from the place, works its jaws for several seconds as though chewing. At the 

 same time a thin stream of sand is seen to come from its mouth. At intervals there 

 is a sudden spurt of water and sand from its mouth so violent that it disturbs the 

 bottom. When the fish has ejected all the sand it moves a short distance with its 

 pectorals in close contact with the bottom and repeats its feeding movements. Wherever 

 it has thrust its snout into the bottom there is left a deep pit which is usually a sharp 

 mold of its snout and the lower part of its head. The pits are connected by broad 

 sinuous trails made by the pectoral fins of the fish. These suggest the tracks of a huge 

 snail and show oblique parallel lines where the edges of the pectorals have pressed against 

 the sand at each stroke. These pits and trails are very characteristic impressions, and 

 are abundant in shallow water throughout the summer. They are more numerous in 

 protected places where the bottom is made somewhat coherent by the formation of 

 marl, and where it possibly contains a larger percentage of nutritive matter. These 

 "tracks" of the sucker enable one to tell each morning where they have been feeding 

 during the night and in what abundance. 



Great numbers of dead suckers are thrown up on the beach in South Fishtail Bay 

 in July and August. Many of these have the characteristic form of starved fish. The 



