PACKARD.] PHYLLOPODS OF NORTH AMERICA. oe 
two species; the fringe of hairs is very long; the gill itself is narrower 
than in L. couesii or bilobatus. In the tenth pair of limbs the third and 
fourth endites are much longer and narrower than in L. couesii, the gill 
and flabellum very different from the other two species, the gill being 
small, pyriform, with a constriction near the end, while the flabellum is 
nearly as broad as long, rounded anteriorly, and with the posterior edge 
straight. 
In the eleventh pair of limbs, bearing the ovisacs, the endites are 
also longer and narrower than in L. couesii. 
Length of body, 14"; of carapace, 10™™; breadth of carapace, 9™™. 
Length of cercopoda, "Gmm , ot telson, 13™™. 
Localit y.—Received from Southern Greenland, through Dr. C. F. Liit- 
ken; Jacobshavn, North Greenland (Gerstaecker, 1064); Cape Krusen-. 
stern, Arctic America (Richardson). 
LEPIDURUS COUESII Packard. 
Plates XV, figs. 2, 2a; XVII, figs. 2, 3,7; XXI, figs. 4, 5, 6, 9, 11. 
Lepidurus couesit Pack. American Naturalist, ix, 311, 1875. Bull. U. S. Geol. and 
Geogr. Survey, F. V. Hayden, in charge, iii, No. 1, 177, fig. 16. April 9, 1877. 
Compared with Lepidurus productus Bose of Europe, the carapace is 
of the same proportions, being large, broad, and leaving above five en- 
tire terminal abdominal segments exposed, including the telson. The 
denticulations on the hinder edge of the carapace are finer than in the 
European species, and show a tendency to become obsolete on the lower 
part of the incision. The eyes are slightly fuller, more prominent than 
in L. productus, and the interocular tubercle is smaller. The mandib- 
ular area of the carapace is the same as in L. productus. Labrum a little 
smaller than in J. productus. The feet are the same as in L. productus. 
The mandibles in this species (Pl. X XI, fig. 11) have, on the cutting 
edge, six well marked teeth, which are rather blunter, less attenuated 
at the end than in Apus lucasanus (fig. 12). The maxilla (Pl. XXI, fig. 
9) has a three-toothed lobe externally, and the inner larger lobe is setose 
throughout. There are usually from ten to twelve spines on the penulti- 
mate segment, as in L. productus. The chief distinction lies in the very 
long spatulate telson, which is about twice as long in proportion as that 
of L. productus, and is long and narrow, varying somewhat in width, and 
in size. The median ridge and edge are finely spinulose, the tip is well 
rounded; caudal stylets nearly as Tone as in L. productus. 
The egos of this species, Pl. ay are somewhat larger than those of 
Apus lucasanus (Pl. XVIII, fig. 5; the figures of the ovisacs containing 
them having been drawn to the same scale by the camera lucida). 
From L. glacialis Kroyer, of Greenland, it differs in the longer, larger 
carapace, eleven terminal segments being uncovered in Te glacialis. 
The spines ou the excavation are much smaller; telson twice as long, 
and not subtriangular, and excavated at tip, as in L. glacialis; eyes 
larger; interocular tubercle decidedly smaller; labrum smaller. The 
first pairgt legs are much longer than in L. g glacialis, in which the endites 
are very short. 
Length of an average specimen from head to end of telson, 20.27; 
telson, 5mm: stylets, 15-19™™, 
This species was collected by Dr. Elliott Coues, naturalist of the 
United States Northern Boundary Commission. He writes me that they 
“occurred in myriads in several small prairie pools, from a hundred 
yards to a half mile or so wide, exactly on the boundary-line, 49° N., just 
