Description of Neiu Species of Diatoms. 17 



the government reports. The deposit is fluiviatile, recent 

 tertiary. 



Amphora tnucronata, n. sp. H. L. S. Hab. Atlantic Marshes, 

 Cape May, N. J., F. W. Lewis, M. D. Frustules in f. v. broadly 

 oval, dorsum with distant longitudinal lines, ventral surface with 

 indistinct longitudinal lines, or furrows, central nodule elong- 

 ated and pointed (mucronate), and touching the margin of the 

 connecting zone, which is of variable breadth, nodules at the 

 end quite small. Median line strongly and sharply inflected 

 and minutely punctate along its whole length, an irregular 

 row of minute lines or elongated dots on the valve within the 

 margin. In s. v. dorsum very convex; ventral margin straight, 

 or nearly so, with slight constriction at the ends; central nod- 

 ule indistinctly shown (out of focus). Striae excessively mi- 

 nute. Length .0026; breadth ,0012 to .002. Plate III, fig. 9. 



I received the gathering containing this very pretty diatom 

 many years ago from Dr. Lewis, and I had entirely forgotten 

 a pencil sketch which he had sent to me at the same time, 

 when I issued it as No. 38 of the " Species Typicae Diatoma- 

 cearum," under the name of A. mucronata. I regret that I did 

 not name it after the discoverer, who, doubtless, would have 

 described it, if he could have continued his excellent studies 

 of the diatomaceae. It has a close resemblance to Ainphiprora 

 hyalina of Dr. Greville, described in his paper on Hong Kong 

 diatoms in '■''Ann. and Mag. Nat. Hist.., July, 1865," though his 

 figure does not show the peculiar mucronate central nodule. 

 The present species is not an Amphiprora, and, therefore, if it be 

 Dr. Greville's form, which is not unlikely, his specific name 

 must be changed, as there is already an Amphora hyalina. It 

 belongs to the so-called ^''Complex Amphorae'' of Gregory, and 

 like A. Cojnplexa it is very tender, scarcely standing strong acid 

 treatment, or even continued burning at a red heat, without 

 injury. 



Actitiocyclus Niagarae, n. sp. H. L. S. Hab. Lake Erie, Cleve- 

 land, O. H. C. Gaylord, Esq. Disc large, diam. .0038, valves 

 very much inflated and densely packed with minute radiating 

 punctae, which are scattered loosely and irregularly at the 

 centre, and sometimes radiate from two central blank spaces. 

 In the living form, the connecting membrane is broad, and the 

 highly inflated valves cause it to lie obliquely. There is a 

 characteristic circlet of minute spines, within the margin of 



