550 rROCEEDINGS OF THE NATIONAL MUSEUM. vol. 47. 



of the body, half way between the dorsal ridge and the lateral mar- 

 gins of the lorica. The ventral plate has an indistinct groove on 

 each side, close to the lateral margin, as shown in the cross section 

 of the body, figure 5. The anterior dorsal margin is straight, the 

 ventral has a deep, V-shaped sinus. The foot opening is long, nar- 

 row, and nearly parallel sided. The foot is long and slender; it has 

 four joints, the posterior being nearly as long as the thi-ee anterior 

 joints. The toes are straight, excessively long, and taper gradually 

 to acute points. 



Total length, 128 pt; length of lorica, 86 /i, width, 54 /«; depth, 39 ji; 

 width of anterior sinus, 29 /x, depth, 18 ^; length of foot opening, 

 25 fjL, width, 15 ft; length of foot, 39 /i, of last joint, 15 fx; length of 

 toes, 27 pL. 



Type.— Csit. No. 16586, U.S.N.M., from Kenilworth, District of 

 Columbia, where the species occurs in weedy ponds, not very com- 

 mon. Isthmian specimens are from a stagnant pool at Empire (4), 

 few; Rio Trinidad, at Escoval (11), few. 



LEPADELLA CYRTOPUS, new species. 

 Plate 16, figs. 6-8. 



The body is broadly oval and evenly rounded dorsally; the ventral 

 plate has near each lateral edge a very shallow longitudinal depres- 

 sion. The anterior dorsal margin is nearly straight; the ventral 

 plate has a very deep, evenly rounded anterior sinus. The foot 

 opening is short, very broad, and widest posteriorly. The moderately 

 long foot has four joints; the fii'st, second, and fourth are nearly 

 equal in length and the third joint equals the combined length of 

 the first and second. The moderately long toes are asymmetric; the 

 right toe tapers rapidly for half its length and ends in a veiy slender, 

 acute point; the left toe tapers gradually to the point and is strongly 

 decurved. The last joint of the foot is twisted, so that the curved 

 left toe is almost directly under the right. 



Total length, 98 /x; length of lorica, 70 ji, width, 56 ft, depth, 29 ju; 

 width of anterior sinus, 24 fi, depth, 19 /i; length of foot opening, 

 17 //, posterior width, 15 /x; lengtli of foot, 32 /x, of third joint, 11 fx; 

 length of right toe, 16 //. 



Type.— C&t. No. 16585, U.S.N. M., from a creek flowing into 

 Camacho Reservoir (3), where the species is common. It also occui'S 

 in a pool near the railroad, between Black Swamp and Gatun (2), 

 few; stagnant pool at Empire (4), few; Rio Grande Reservoir (5), 

 common; Rio Grande (6), few. 



COLURELLA BICUSPIDATA (Ehrenberg). 



In a creek flowing into Camacho Reservoir (3), few; Rio Grande 

 Reservoir (5), few. 



