240 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. 



lateral row of scales; terminal claw with a small spine. Tlie shell is 

 ornamented with fine, close, longitudinal striations. Length 0.9 mm. 

 Alona elegcms is very near to this and should have followed. In August, 

 1878, I took an Aloiia marked as in A. mnguinea and agreeing with 

 Mueller's description in all points which can be verified in the draw- 

 ing. The small size of the eye is remarkable for so large an animal. 

 I have never again seen this species; it seems to be very rare here and 

 in Europe. 



Alona inoniezi Richard. 



Richard '88. 



"Testa antice quam postice latior, striis ruultis, interdum areis ornata, supine sat 

 arcuata, postice fere truncata, angulo inferiore rotiindato, inferne subrecta, ciliis 

 loBgis, hie obsita. Antenrfe Imi paris apicem rostri fere attingeutes. Articulus 

 ultimus utriusque rami antennarum 2 di paris, setis 5 loDgis et aculeo forli piseditus. 

 Rami exterioris articulus penultimus longa seta instructcs. Macula nigra oculo 

 major, inter hunc et apicem rostri in medio sita. Post-abdomen breve latitudine fere 

 sequali, ad angulum posteriorem et inferiorem rotundatum, seriebus (8-9) aculeorum 

 (4-5 quorum exterior multo major) fusiformium, pia;terea aculeis minutis sequalibus 

 fasciculatim usque ad processum obtusum positis, armatum. Adest denique series 

 lateralis squamarum spinis gracilibus ac longis compositarum. Ungues teiminalfs 

 sat longi, usque ad apicem ciliis minutissimis obsiti, dente basli gracile, et sat magna. 

 Sefte abdominales longje. Mas femina majore paulo dicrepans. Postabdomen brevius, 

 latum, spinis unguibusque terminalibus multo brevioribus quam infemina, oTuatum. 

 Pedes 1 mi paris in hamulo valido curvato ad basin crasso, apicem versus acuto ex- 

 euntes. Longit. fem., 0.5-0.55 mm.; mas., 0.45-05 mm." 



Found near Vichy. 



* Alona quadrangularis Miiller. 



Plate LXI, Figs. 1, 2. 



Alona oblonga — P. E. Mueller. 



Alona affinis — Leydig. 



Alona sulcata — Schoedler, Hudendorflf. 



The group of forms included under the above names is in inex- 

 tricable confusion. Hellich evidently describes the same species as 

 quadranfiularls and offixi.s. Ajfitiis falls little short of one millimeter in 

 length while quadranguJaris is less than 0.75 mm. A. oblonga is said by 

 Kurz to measure 0.8 to 0.9 mm. He, however, did not know A. affinis. 

 Hellich says that there is a secondary marking of the shell in A. affivis. 

 The claws are smooth in quadranguJaris and ciliate or toothed in affinis. 

 Statements of various authors diifer respecting the relative size of eye 

 and pigment fleck. 



The American form, which most closely approaches affinis, has the 

 claws denticulate and the pigment fleck smaller than the eye. In the 

 figure (Plate LXIV, Fig. 14) the head is somewhat protruded by 



