ENTOMOSTRACA OF MINNESOTA. 67 
much thickened. The antepenultimate joint bears a small hook and 
the last two joints are relatively very small, The antennules are of 
the usual form, the two-jointed branch being much the shorter. The 
first feet of both sexes have, as usual, the inner ramus two-jointed. 
The external spines of the outer ramus are longer in the male. The 
fifth feet of the female have the inner ramus very long and two jointed, 
armed apically with two very long, setose, equal spines. The apical 
segment of the outer ramus is distinct and armed with two subequal 
spines, and is protected by a spine from the preceding joint near its 
base. The claw is strongly toothed and straight. The right foot of 
the male is much longer than the left and has a short toothed apical 
claw. The accessory spine is near the base of the claw.. The inner 
ramus is very small and spatulate. The preceding segment bears a 
small spine externally and a lamellate appendage within. The inner 
ramus of the left foot is larger and nearly as long as the basal joint of 
the outer ramus; it is corrugate internally and bears a short spine 
apically. Opposite this ramus on the basal segment of the outer are 
small sete. The apical segment of the outer ramus bears two curved 
Spines and numerous set apically and a hairy plate internally. 
Length 3.0 to 4.0 mm. 
This species has been found in Minnesota, Illinois, Ohio, Kentucky 
and Alabama. 
* Diaptomus albuquerquensis Sp. n. 
PLATES VI, Fias. 1-3; VII. 
Magnitudine mediocri, Cephalothorax latitudine maxima ad medium sita; seg- 
mento ultimo feminz ad latera extante, utrinqgue mucronibus 2 armati. Segmentum 
abdominale 1-mum partem reliquam abdominis, setis exceptis, longitudine superans, 
utrinque mucrone distincto preditum; segmentum 2-dum per breve. Rami furcales 
segmento antecedente fere zequantes, intus ciliati. Antennze 1-mi paris extremam 
furcam attingentes, vel superantes, 25-articulate. Articulus antepenutimus anten- 
nee prehensilis maris processu recto vel subanguiformi sat longo preeditus. Pes 5-ti 
paris femine ramo exteriore triarticulato, articulo 3-tio perspicuo, et aculeo interiore 
circiter ad medium processus unguiformis articulo 2-di porrecto. Processus ungui- 
formis modicis arcuatus, dentibus ad partem medium armatus. Ramus ejus interior 
extra medium sed non ad finem articuli 1-mi rami exteriores porrectus, biarticulatus, 
et ad finem ciliatus. Pes dexter 5-ti paris apud marem ramus interior 1-articulatus, 
per breve, articuli antepenulti rami exterioris longitudinem equant. Unguis (vel 
segmentum 3-dum) per magnum, in longitudine pars religuis pedis superans. Pro- 
cessus lateralis segmenti 2-di magnus, ad basin intus dentibus minutibus affectus. 
Pedis sinisteri 5-ti paris apud marem, articulus ultimus rami exterioris conicus, in- 
tus lamina ciliatus instructus, ad apicem mucronibus duobus affectus. Segmentum 
2-dum ejus ramus, intus granulosus. Ramus interior previs, uni articulatus. Ani- 
mal pleurumque pellucidum, colore albido.. Longitud. feminze 1.4-1.6 mm. 
This medium sized species occurs in the water reservoir supplying 
Albuquerque, New Mexico, together with D. novamexicanus in large 
numbers. The last segment of the thorax is protuberant and bears 
5 
