86 TWELFTH ANNUAL REPORT. 



This form I have never seen, and it seems somewhat doubtful that 

 the following really belong with it. 



Sp. 3, Aloiiopsis latissinia, Kurz. 

 (Plate E, Fig. 8. Plate G, Figs, 1 and 9.) 



Body ver> high, compressed, with a high dorsal keel or ridge; 

 the upper outline strongly and evenly arched, terminating be- 

 hind in no angle; lower margin almost angled at the anterior thirds 

 rounded behind, fringed with long bristles anteriorly, with short 

 ones posteriorly. Head very narrow; beak extremely long; fornices 

 small; antennules nearly as long as the beak, straight and narrow; 

 pigment fleck smaller than the eye. The abdomen is long, some- 

 what narrowed toward the end, where it is deeply cleft^ the terminal 

 claw is furnished with a large and small basal spine, while there is 

 an increasing series of spines extending to the middle. 



The elongated spine of the third foot is pectinate and reaches 

 nearly to the posterior margin of the shell. The shell is marked 

 by few strong striae which are diagonal except anteriorly where are 

 a few parallel to the front margin. The male is small and lacks 

 the crest on the back, while the lower margin is straight; the an- 

 tennae are longer than the beak and differ somewhat from those of 

 the female. The first foot has a claw. The post-abdomen lacks- 

 the anal teeth. Kurz gives the size as 0.5 mm. 



The A.merican form varies between 0.45 mm. and 0.55 mm., and 

 seems to have a higher dorsal keel and longer beak. Kurz speaks 

 of but a single accessory spine on the terminal claws; there is, how- 

 ever, a second very minute spine or cluster of hairs in this as well 

 as the following. 



Found in the same gathering with the following near Minnea- 

 polis (marshy off-set from Bassett's creeknear Oak Lake Addition).* 



*NOTE TO ALONOPSis LATissiMA. (See Fig. 1, Plate G.) Since writing the above tlie 

 males of our American form have been found ; they are shaped as the females, with a 

 high dorsal keel ; the post-abdomen is rounded, with transverse series of small bristles ; 

 the claw has a minute median spine, and the iwrus genitalis is anterior and elevated. 



Sp. 3. Alonopsis media, Birge. 

 (Plate E. Fig. 9,) 



I give Birge's description verbatim: 



"Rostrum prolonged, and shell sharp, somewhat quadrangular in 

 shape, marked by striae. The dorsal margin is convex, the hinder 

 margin nearly straight. Its lower angle is rounded and without 

 teeth. The lower margin is concave and has long plumose setae^ 



