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BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



claws (one shorter than the other three), and two moderately long seta?, 

 and one long one from the end of the penultimate joint, besides four 

 rather long ones above, and two beneath about its middle. Third joint 

 with the usual single stout seta from its end beneath, and the usual fas- 

 cicle of five long and one short one above near the end, and the usual 

 articulated process. Post-abdominal ramus similar to that of C. incon- 

 gruens as figured by Brady {loc. cit., plate 23, fig. 20), but longer, having 

 three unequal setse, the terminal one longest. Seminal gland very sim- 

 ilar to that of Notodromus monaclms {loc. cit., plate 37, fig. 36). 

 Length, i of an inch; height, jL j greatest thickness, Jg.. Probably the 

 largest known species of the genus. It is abundant in ponds along the 

 Upper Arkansas Eiver in the Mount Harvard region, at an altitude of 

 about 8,000 feet. When first taken, my specimens were brownish from ad- 

 hering mud, but alcoholic specimens have the livid white color above 

 mentioned. The lucid spots are indistinct and difficult to make out; 

 there are about nine, the two anterior obliquely transverse and long, 

 the two posterior small. 



C. altissiniiis n. sp. (Fig. 2). — Valve oblong, slightly subreniform, high- 

 est about the middle, rounding regularly before and behind; the side- 

 view resembling somewhat Baird's figure of C. tristriata, but less dis- 

 tinctly reniform, perhaps rather resembling in the form of the dorsal 

 margin Cypridopsis vidua; it is, however, much more elongate in pro- 

 portion to height. Brady's figure of C. virens (= C. tristriata Baird) is a 

 little nearer to this species, but is too distinctly reniform. C. virens also 

 agrees with this species in the number (se.veu) of the lucid spots, and 

 approaches it in their position on the shell, and in relation to each other, 

 but they are differently shaped. In this species, the extremities are more 



Fig. 2. — Cypris aliissimus, Cha:m., n. sp. 



nearly equally rounded than in mrens, the dorsal margin being evenly 

 rounded before and behind the middle, and the ventral likewise, both 

 before and behind the slight sinuation in the middle. But the anatomy 

 of the appendages differs more decidedly from that of virens, as will be 



