44 UNIVERSITY OF COLORADO STUDIES 



(135) Ceriodaphnia Dana. C. dentata Birge. Boulder (Dodds). 



(136) Scapholeberis Schoedler. 5. mucronata (O. F. Muller). Boulder (Dodds). 



(137) Simocephalus Schoedler. . S. serrulalus Koch. Boulder (Dodds). S. vetulus (0. 

 F. Muller) Boulder and Redrock Lake (Dodds). 



(138) Daphnia O. F. Muller. D. pulex (DeGeer)* University campus (Dodds). 

 Dodds reports D. dentifera Forbes from Redrock Lake and Tolland, but is not 

 positive about his identification. 



Family LYNCODAPHNIIDAE 



In Drepanothrix Sars, known from Twin Lakes (D. denlaia Eur6n), the four- 

 jointed branch of the second antenna has only three swimming hairs; 1 in Macrothrix 

 W. Baird this branch has four swimming hairs. 



(139) Macrothrix W. Baird. M. laticomis Jurine. Near Boulder (Dodds). 



Family CHYDORLDAE Leach 



Subfamily EURYCERCINAE 

 Six pairs of thoracic limbs; head and thorax separated by a deep depression; 

 female carries many summer-eggs (Weldon). 



(140) Eurycercus W. Baird. E, lamellatus (O. F. Muller). Tolland (Dodds). 



The antennules have a crown of long teeth around the apex, from within which 

 arise the sense-hairs; on the basal joint of the antennae, about the middle of its 

 hinder side, is a large tubercle, covered with short, stout, black spines (Birge). 



Subfamily CHYDORINAE 

 Five pairs of thoracic limbs; head and thorax separated by a slight groove or not 

 at all; female carries only one or two summer-eggs. 

 Body small, spheroidal, the head depressed; compound eye present 



Chydorus Leach. 



Body more elongate or oval 



Head carinate, the eye (as seen in lateral view) far from the anterior cephalic 

 margin; second antennae with seven swimming hairs; telson more than 

 half as long as carapace .... Camptocercus Baird (Twin Lakes). 

 Head not carinate, the eye near the anterior cephalic margin. 

 Terminal claws of telson with three accessory teeth 



Alonopsis Sars (near Greeley). 

 Terminal claws of telson with two accessory teeth . Pleuroxus W. Baird. 

 Terminal claws of telson with one accessory tooth 



Alona W. Baird, Graptoleberis Sars, and Dunhevedia King. 

 Terminal claws of telson small and unarmed Graptoleberis inermis Birge. 



(141) Graptoleberis Sars. G. lesludinaria Fischer. Common in several lakes near 

 Boulder (Dodds). 



(142) Alona W. Baird. A. guttata (Sars), Boulder (Dodds); A. quadrangularis (O. F. 

 Muller). Boulder and Redrock Lake (Dodds). 



1 If Drepanothrix and other Cladocera are placed with water in a watch glass, and exposed to a strong 

 light, Drepanothrix will hurry away from the light, while Chydorus, Pleuroxus, Daphnia, etc., will approach 

 the light (Birge). 



