THE FAIRY SHRIMPS (PHYLLOPODa) 671 



36(1) Body with a well-developed carapace .^ 



37 (52) Body depressed, covered dorsally by a depressed shield. 



Suborder Notostraca 38 



38(45) Telson ending in a long, paddle-shaped outgrowth. . Lcpidurus . 39 



39 (40) Telson short, obtusely pointed, spiny on edge. 



Lepidurus glacialis Kroyer 1847. 



|?f~5J| ^^ arctic species recorded from Greenland and Labrador. The larapace 



11^ nIS ^^ ^^'^^ '^""^^ ^"^^ regularly ovate; twelve segments are exposal behind it. 



^'ff V.Wp Fig. 1031. Lepidurus glacialis. Telson. X 6. (After Packard.) 



40 (39) Telson spatulate. ^ i 



41 (42) Telson carinate dorsally; carapace large, leaving only five body seg- 



ments and telson uncovered. 



Lepidurus coucsii Packard 1S75. 



This species occurs in Utah where it frequents prairie p(x>ls of 

 various sizes. 



Fig. 1052. Lepidurus couesii. Telson. X 6. (After Packard.) 



42 (41) Telson not carinate dorsally 43 



43 (44) Telson long bilobed; carapace short, without spinous crest. 



Lepidurus bilobatus Packard 1S77. 

 This species has not been recorded since the Hayden survey, when it was taken in Colorado. 



44 (43) Telson long, not carinate, sometimes bilobed; carapace with a median 



spinous crest Lepidurus lemmoni llolmvs iS(j4. 



California. The cercopods are very long in this species. 



45 (38) Telson short, cyHndrical, simple ipus . . 46 



46 (47) Carapace as long as the portion of the abdomen projecting beyond 



it; telson short with two median and two lateral spines on 

 its dorsal median third. . . . A pus acqualis FacksiTd iSyi. 



V^ >l\ A widely distributed species occurring in Mexico. Lower California. Texas, 



t^> ,^\ Nebraska, and Kansas. It [has 23 segments exposed behind the carapace. 



^'^^^-■'^ Fig. 1012 shows the form of this species. 



Fig. 1033. Apusaequalis. Telson. X 6- (After Packard.) 



47 (46) Carapace shorter than the portion of the abdomen exposed behind 



it 48 



48 (49) Telson long, with three median and two lateral spines on its dorsal 



median third; 29 segments exposed behind carapace. 



Apus nnvhcrryi V:icka.Td 1S71. 



% '^ "^ Recorded from Utah and Colorado. The hairs along the cercopods arc 



I y J> , \ said to be remarkably fine. 



pr^^l Fig. 1034. A pus ncu'bcrryi. Telson. X 6. (After Packard.) 



49 (48) More than 30 segments exposed behind carapace. 



^0 



