NATURAL HISTORY SOCIETY OF GLASGOW. 215 



Another species placed by all in Cocconeis, is C. hinotata of 

 Grunow: that this is identical with C. scutellum of Eoper, is by 

 all acknowledged, but it is not so well known that it is the same 

 with C. Bntannka of Naegeli, described, in 1849, in Kiitzing's 

 Species Algarum, p. 890. This I consider a very doubtful species of 

 the scenus. I have examined it on the v/eed, and detached from 

 it by calcining it, and with the valves separated by acid, and can 

 see no difference between the two valves. In one instance I found 

 the two valves so slightly separated that part of the one covered 

 part of the other; both had the same striation, the same marginal 

 plates at the middle of each margin, the same nodule, and median 

 line. The presence of the small marginal plates at first sight 

 indicates Masfogloia as its genus; but now this affinity is not 

 without difficulty. I saw one instance, where what appeared to be 

 the zone (which connects the valves of diatoms) had separated, 

 carrpng with it the plates to which I allude; they are without 

 striae, and onlj'" appear striated when attached to the valve, the 

 striae of the valve being seen through them. In Masfogloia, the 

 marginal plates also occasionally separate from the valve, and, 

 according to Smith, are projections from the zone ; but in all the 

 recognised species they are marked by costse, Avhile in C. hinotata, 

 there are none. This, however, and its being attached to weeds 

 by the back of the lower valve, not free and immersed in gelatine, 

 leave doubts as to Masfogloia being its proper genus. C. fimbriata, 

 Ehrenberg and Brightwell, is probably a species of Masfogloia; 

 but as yet it is only known by stray valves, which are not suffi- 

 cient to indicate the genus. 



As I have noticed Masfogloia, I may here mention that four of 

 the species mentioned by Smith — M. Dansei, M. lanceolata, M. 

 Smithii, and M. apiculafa, according to the careful measurements of 

 my friend, Mr T. Glazebrook Eyland, of Warrington — have all the 

 same striation and the same number of loculi in "001; in all, the 

 striae are 41 in '001, and the loculi 20'5 in -001, so that there are 

 two striae to each loculus — perhaps all these are therefore the same 

 species. In M. Grevillei there is a difference. Here the loculi 

 are about 19, the striae 24*5 in '001, and there are seven loculi to 

 nine striae. In a species I lately observed very sparingly (I have 

 only as yet seen three valves), the striae were so obscure that I 

 could not see them -vvitli any of my lenses, while the loculi, of 

 which there were only about three to a plate, were 10 in -001. 



