Navicularea.] infusorial animai-cfles. 421 



PiNNXTL^uaA contract a. — The same habitat. 



P. tceniata. — Small, on dorsal aspect, umbilicus distinct ; pinnules, 

 marginal, strong, ends suddenly constricted, prolonged, rounded, and 

 obtuse. (P. 24, f. 15.) 



P. Australis, P. pleuronectes, and P. styliformis, new species dis- 

 covered by Ehrenberg in earth from New Holland. 



P. ampJmtijlus. — Bacillar, elongate, turgid at the middle ; apices 

 attenuate, filiform, obtuse ; pinnules fine. Length 1 -372nd. Fossil 

 in Oregon. 



P. leptostigma.-^O'hlong-ldincQolaie, length twice its breadth; 

 apices subacute, rather produced ; very fine transverse dotted lines, 

 (pinnules) inconspicuous. Length 1 -432nd. Fossil. 



P. Oregonica. — Elongate, navicular, bacillar, uniformly and 

 gradually decreasing towards the rounded apices ; pinnules strong, 

 twenty -three in l-1152nd. Length l-228th. Fossil in Oregon. 

 It approfvches P. Digitum, but is more slender. 



P. Sckomhurgliii. —Itarge, lanceolate, equal, length thrice its 

 breadth; apices subacute; pinnules twenty-five in 1 -1152nd. ; ap- 

 proaches P. cequalis, but is smaller and more obtuse. Length l-264th. 

 Guana. AUve. 



P. Couperii (Bailey.) — Large, slightly constricted in the middle, 

 with two marginal and two intermediate punctato-striate bands, the 

 latter interrupted at the centre. The outline is like that of P. para- 

 doxa (Ehr.), and the markings somewhat resemble those of P. lyra. 

 Southern States of America. 



P. permagna (Bailey.)— Large, lanceolate on the ventral surfaces, 

 with punctato-striate marginal bands ; and a broad, smooth, central 

 stripe ; ends slightly rounded. Abundant in the Hudson Eiver, at 

 "West Point, New York. 



P. eequinocfiaUs (Montague.) — Rather large, linear-oblong, apices 

 rounded, pinnules radiant, strong, four in 1 -2600th. Length of 

 fiaistule 1 -260th. to 1-1 50th. Found with Algte in British Guiana. 

 It, in general fonn, resembles P. Dactylus, but differs in its size and 

 larger striae. In the last particular it resembles P. pacliyptera, 

 but that species has a median dilatation or gibbosity. Montao-ne, in 

 his notice of the ciyptogamic plants of Guiana, (Ann. de. sc. Nat. vol. 



