£22 E. GROVE AND G. STURT OX 



tender our hearty thanks. We have also to acknowledge the kind 

 aid and assistance rendered by Dr. Stolterfoth, of Chester, and by 

 Mr. F. Kitton, in the examination and identification of species ; 

 and of Mr. Rattray, of Dundee, in the preparation of magnificent 

 picked slides. 



In the course of a careful examination of many slides we have 

 observed the following genera and species. In addition to these, 

 some extremely doubtful forms occur, which for the present are 

 omitted, as they require considerable further investigation : — 



Cymbelle^e. 



Amphora labuensis, Cleve (" Vega Exp.," p. 493, PI. 35, Fig. 

 10), — Scarce. 



A. cingulata, Cleve (" W. I. D.," p. 9, PI. 3, Fig. 15). —One 

 specimen observed closely resembling the figure in A. Schni. Atl., 

 PI. 26, Fig. 17, but with a less clearly developed "cingulum." 



A. crassa, Greg. (" G. D. C," p. 52, PI. 6, Fig. 94).— One 

 specimen observed. 



A. sp. ? sp. ? — Some doubtful fragments detected. 



CoCCONEIDE^E. 



Cocconeis barbadensis, Grev. (" T. M. S.," 1864, p. 14, PI. 11, 

 Fig. 10). — Occurs sparingly, and is smaller and more lanceolate 

 than Greville's figure. The median line is undulate, and the form 

 is probably an Orthoneis. Longest diam., about '003". 



C. pseudo-marginata^&x. intermedia, Grun. ("Nov. Exp.," p. 

 13, PI. 1, Fig. 6). — Not uncommon. 



Campyloneis {Grevillei var. ?) argus, Grun. (" V. H. Syn. Belg. 

 Diat.," PI. 28, Fig. 16).— Not uncommon. 



Mastogloia reticulata, Grun. (Honduras Diatoms, in "M. M. J.," 

 1877, p. 175, PI. 195, Fig. 4). — Closely resembles Grunow's form, 

 but is much longer (up to *007"). Three specimens observed. 



NAVICULACE.E. 



Navicula apis, Ehr. (Donk., " Brit. Diat.," p. 48, PI. 7, Fig. 3). 

 — A small form, exactly resembling Donkin's figure. Two or three 

 larger specimens have occurred up to '004" in length ; rather less 

 constricted, and approaching N. didyma, Ehr. 



N. Smithii,- var. nitescens, Greg. (" G. D. C," p. 15, PI. 9, Fig. 

 16). — Scarce. 



N. gemmata, Grev. (" Ed. New Phil. Journ.," Vol. x, p. 30, PI. 

 4. Fig. 7 ; vars. A. Schm., "Atl.," PI. 8, Figs. 38.42).— Eare. 



