712 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [12] 



quette and l'Anse differing from those described by Professor Birge 

 only in slight detail. None of the stria) of the shell take a direction to 

 meet the ventral margin at right angles, but ail incline backwards ; the 

 plumose setre of the ventral margin are not sparse, but are placed as 

 thickly as they can stand ; and the anterior margins of the shell are not 

 dentate, but the setae there are articulated by greatly thickened bases. 



Chydorus sphaericus Baird. 



Taken frequently in small numbers in both lakes. 

 Chydorus rugulosus 11. sp. 



Allied to C. splimricus, but with the depth only three fourths the length, 

 the pigment speck nearly or quite as large as the eye and half as far 

 from the eye as from the tip of the rostrum, and the hexagonal shell- 

 areas marked by a delicate reticulum of minute rugosities. 



Shell highest at middle, scarcely truncate posteriorly, but the hind 

 margin rounding broadly into the lower, the anterior dorsal surface 

 flattened, meeting the flattened valves at an acute projecting angle, 

 giving the shell a trigonal form like that of a beech nut. The dorsal 

 outline not uniform, but flattened in front. Submarginal row of hairs 

 along the ventral edge rather coarse and strong — about four to the 

 length of a marginal hexagonal area. Surface of the shell everywhere 

 distinctly reticulate, bearing besides the coarse hexagonal reticula- 

 tions, a very tine but distinct net-work of minute rugosities, the meshes 

 of which are longest in the direction of the margin of the shell. 



The labial appendage long, reaching as far as the tip of the rostrum, 

 and as broad at the base as high. The posterior inferior angle pro- 

 duced and extending slightly backwards, the whole quite different in 

 form from that of C. sjyhwricus. 



Post abdomen short, broad, inferior margin broadly rounded, with 

 nine or ten simple, stout teeth. Anal tubercle forming an acute angle; 

 the caudal claw smooth, with a small basal tooth, the length of which 

 is about equal to the diameter of the claw. 



Length, .5 mm ; depth, .38 mm ; width, .33 mm . 



Collected in considerable number from the surface in Marquette har- 

 bor at 5 a. in., August 11, 1889, and less abundantly August 9. 



Chydorus globosus Baird. 



Seemingly less abundant than the preceding. Noticed only at l'Anse. 



Bosmina longirostris O. F. M. 



A few specimens of this common species — the only one of its genus 

 noticed — were taken repeatedly at Marquette, at White Fish Point, and 

 at l'Anse. 



Family Daphniidje. 



Scaphloberis mucronata O. F. M. 



This abundant European eutomostracan occurred in the very miscel- 

 laneous collections from l'Anse, but was not noticed elsewhere. 



