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232 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. 
*Alonopsis latissima Kurz. 
PLATES LXI, Fie. 8; LXIII, Fires. 1 and 9. 
Body very high, compressed, with a high dorsal keel or ridge; the 
upper outline strongly and evenly arched, terminating behind in no 
angle; lower margin almost angled at the anterior third, rounded be- 
hind, 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, somewhat 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 
a few strong strize which are diagonal except anteriorly where area 
few parallel to the front margin. The male is small and lacks the 
crest on the back, while the lower margin is straight; the antenne 
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 American 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, however, 
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 Minneapolis 
(marshy off-set from Bassett’s creek near Oak Lake Addition):* 
* Alonopsis latissima var. media Birge. 
PLATE LXI, Fie. 9. 
I give Birge’s description verbatim. 
‘*Rostrum prolonged, and shell sharp, somewhat quadrangular in 
shape, marked by strie. 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 sete. The 
front margin is strongly convex. The post-abdomen is long and slender, 
resembling that of Capmtocercus, and is notched at the distal extrem- 
ity; it has two rows of fine teeth and some fine scales above them. 
The terminal claws are long, slender, with a basal spine, a spine in 
Note To ALoNopPsis Latissima. (See Fig. 1, Plate LXIII.) Since writing the above the 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 porus genitalis is anterior and elevated. 
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