PACKARD.] PHYLLOPODS OF NORTH AMERICA. 307 
two-thirds as broad as long, with the umbones or beak rather prominent, 
oblique, situated on the anterior fourth of the shell, which is fuller, more 
globose than in the foregoing species; dorsal edge straight behind the 
beak, and a little beyond the posterior third of the entire shell rather 
suddenly sloping down, though the end is full and rounded. Shell 
(Fig. 10, in text) narrower than usual in the transverse diameter; about 
sixteen to twenty lines of growth, with fine sete along the lines; un- 
usually fine microscopic punctures between the lines, too numerous to be 
counted with a triplet. Under a higher power the dark spots in the soft 
tissue of the shell are seen to be either separate (Plate XXIV, fig. 3) or 
confluent (Plate XXIV, fig. 6), forming parallel markings, which disap- 
pear before reaching the line above. (The series of oval clear spaces 
in the drawing are the attachment of the setz, which are long and 
slender, see Plate XXIV, fig. 3.) In Baird’s fig. 4a and 6) of H. dunkeri 
the punctures are separate, and probably there is a variation in this 
respect. Male shell narrower, and with rather more prominent beaks 
than in that of the female. Head, with the rostrum, Jong and pointed; 
first antenne rather thick, and moderately long; second antenne with 
rather short joints, 17 in the upper and 16 in the lower flagellum; the 
upper sides of all the joints with 4-5 slender sete; legs of the female, 
with the gill, rather long and large, the lower division of the flabellum 
quite broad; the upper or oviger (Plate XXIV, fig. 9) quite long and slen- 
der, but shorter thanin EH. compleximanus. First and second pair of legs 
of the male with rather slender hands, and both divisions of the flabel. 
Juin are rather short and broad; the claw (sixth endite) is shorter than 
in H. compleximanus, as is the thumb, or fourth endite; the fifth endite 
is much as in L. compleximanus. The telson is shorter and higher than 
in HL. compleximanus, with about twenty pairs of unequal spinules, the 
first, third, sixth, ninth, twelfth, fifteenth, seventeenth, and nineteenth 
much larger than in the others, while in HL. complecimanus they are of 
uniform size; each spine is minutely spinulated; the terminal superior 
spine one-half as large as the inferior, but finely spinulated; the cau- 
dal appendages with fine, hair-like sete on the upper edge. 
The males have stouter spines on the telson than in the other sex. 
Length of shell, 10-12™™; height, 7™™; transverse diameter, 4™™. This 
species differs from KH. compleximanus in the more globose shell, the 
much shorter dorsal edge, which suddenly bends down, the fuller ends, 
the shorter hands of the male, and the unequal spines on the telson. 
From EH. morset it differs in the flatter, more oblong sltell, and in the 
beak being much smaller, more oblique, and much nearer the anterior 
end of the dorsal edge, while the hands of the males are much slenderer 
than in H. morse. 
This is apparently the most abundant and widely diffused species on 
the continent, as will be seen by the following notes: 
Lake Winnepeg, North America (W. Caldwell, esq.); (Mus. Brit.) 
Baird.) 
Several hundred young (figures on Plate X XVIII, figs. 1-6) about one- 
half full size, collected by the laie Prof. H. James Clark from a puddle 
in Lexington, Ky., May 21. 
Cincinnati (Mus. Chicago Academy Science), Hamilton County, 
Ohiv, in a cart rut, “so numerous that a dip of the hand would take 
up a dozen” (V. T. Chambers). 
Ellis, Kans., “in an upland pool supplied by a spring” (Dr. L. Wat- 
son), Fort Wallace, Kansas, in company with Lstheria compleximanus and 
Streptocephalus texanus. (Prof. J. Lindahl.) 
Common at the pueblo of Santa Ilsafonso, New Mexico, August; 
