THE FAUNA OF BOULDER COUNTY, COLORADO 43 



several specimens of Estheria compleximanus Packard. I refer them to E. com- 

 pleximanus rather than to E. mexicana Claus (the only Estheria hitherto in the 

 Colorado list) because the shape of the carapace is exactly as in Packard's figure 

 of compleximanus, and the "hand" and telson (with many more than 20 teeth, 

 though these are not all of the same size) also agrees. The carapace of E. mexicana 

 is less elongated. Thus Mr. Markman's roadside pool at Montclair yielded four 

 species of Phyllopod Crustacea, two species and one genus being new to Colorado; 

 it also contained a mollusc, Galba bulimoides cockerelli (Pilsbry and Ferriss). 



Suborder Cladocera Latreille 



Small, short-bodied animals, with not more than six pairs of thoracic limbs; 

 second antennae used in swimming. They are commonly known as "water-fleas." 



Family SLDLDAE 

 Six pairs of thoracic feet, the first pair not prehensile; second antennae two- 

 branched in both sexes. The genus Latona Strauss 1 (£. selifera Muller) has been 

 found by Juday at Twin Lakes. 



The remaining families, with four to six pairs of thoracic feet, the anterior pair 

 prehensile, may be separated as follows, after Weldon: 



Ventral branch of second antenna with three joints, the dorsal with four 1. 



Both branches of second antenna three- jointed . Chydoridae (Lynceidae). 



1. Five pairs of thoracic feet, with a gap between the fourth and fifth pairs 



Daphniidae. 

 Four (Lathonura) , five {Macrothrix, Drepanothrix, etc.), or six {Acantholeberis, 

 etc.) pairs of equidistant thoracic feet, the first two pairs prehensile 



Lyncodaphniidae (Macrothricidae) . 



Family DAPHNHDAE W. Baird 



Weldon gives the following key to the genera: 



First antennae of female long, mobile; posterior margin of carapace without a 

 spine .... Moina W. Baird. (M . affinis Birge was found by 

 Beardsley near Greeley, often extremely abundant in pools formed by summer 

 rains.) 



First antennae of female short 1. 



1. A median dorsal spine on posterior margin of carapace 2. 



A pair of ventral spines on posterior margin of carapace 



Scapholeberis Schoedler. 

 No spine on posterior margin of carapace . . Simocephalus Schoedler. 



2. First antennae of female not mobile; head separated from thorax only by a 



slight constriction or not at all; cuticle with a quadrate rhomboid pattern 



Daphnia O. F. Muller. 



First antennae of female mobile; head separated by a deep depression from 



thorax; cuticle with a polygonal pattern . . . Ceriodaphnia Dana. 



1 Latona was proposed independently in Mollusca and Crustacea in 1817; I do not know which has 

 priority. I take the date of Latona Strauss from the Nomenclator Zoologicus, but according to Birge, it appears 

 that the work of Strauss was not really published until 1820. 



