THE FAUNA OF BOULDER COUNTY, COLORADO 49 



by the white, shining carapace, with numerous almost confluent punctures, and the 

 terminal short setae of second foot evidently unequal. It is less than 1 mm. long. 

 Cyclocypris Brady and Norman has the species C. laevis (O. F. Miiller), found by 

 Beardsley near Greeley. 



Subfamily CANDONINAE 



Candona W. Baird has the natatory setae of first antenna shorter than antenna; 

 second antenna six-segmented in male and five-segmented in female; furca normal; 

 eye present, small. C. acuminata Fischer was found by Beardsley near Greeley. 

 It is a species of uniform color, white to brownish. These animals cannot swim, 

 but creep along the bottom, or burrow. 



Bairdia McCoy, a genus assigned to the Cyprididae, occurs in the Carboniferous 

 strata in the Leadville district (Girty). 



Subclass MALACOSTRACA Latreille 



Generally large Crustacea, with a definite and constant number of body-segments. 

 In addition to the paired eyes we can distinguish two pairs of antennae, a man- 

 dibular segment, and two maxillary segments composing the head-region proper; 

 there then follow eight thoracic segments, the limbs belonging to the anterior 

 thoracic segments being often turned forward toward the mouth, and modified in 

 structure to act as maxillipedes, while at any rate the last four are used in locomo- 

 tion. The abdomen is composed of six segments, which typically carry as many 

 pairs of two-branched pleopods, and the body terminates in a telson (Geoffrey 

 Smith). Miss Richardson indicates only seven thoracic segments in the Isopoda. 



Order ISOPODA Latreille 



The body is dorso-ventrally flattened, and is divided into three parts — a head, a 

 thorax composed of seven segments and an abdomen of six segments; the head 

 appendages are two pairs of antennae, a pair of maxillipeds, two pairs of maxillae 

 and a pair of mandibles; eyes sessile and compound; seven pairs of legs, the last 

 pair sometimes wanting; marsupial plates developed in the female, forming an 

 incubatory pouch (Richardson). Miss Harriet Richardson has published a mono- 

 graph of the North American species (Bulletin 54, U.S. National Museum). 

 Uropoda lateral, forming together with the terminal segment of the abdomen a 



caudal fan Cymothoidea. 



Uropoda terminal; pleopoda fitted for air-breathing .... Oniscaidea. 



Suborder Cymotholdea 



This group contains the family Sphaeromidae, a genus of which, Exos phaeroma 

 Stebbing, though usually marine, possesses a few fresh-water representatives. I 

 discovered E. thermophilum (Richardson) in a warm spring near Socorro, New 

 Mexico, which remains the only known locality for it. Warm springs, wherever 

 they occur, should be searched for these remarkable animals. 



