4 P. T. CLEVE. DIATOMS FROM JAVA. 



and near the eqiiator in the sea of Java, were exactly identic; 

 pome Rizosolenice, Chcetoeeros Peruviannm and some others oc- 

 curring in both. 



The forms of diatoms fotmd in tlie collection from Java 

 were the following: . 



1. Coscinodiscus Oculus Iridis Ehrb. (M. Geol. PL XVIII 

 (ig. 42 & Pl. XIX fig. 2) variety; very common. 



The variety of this species was distinguished by its ceUules, 

 being larger near the margin of the valve (6 in 0, 02 5 m.m.) 

 and gradnally decreasing in size towards the centre, where in 

 raost specimens is a collection of some few, very large cellules. 

 Smaller specimens cannot be distinguished from C. radiatns- 

 and larger specimens have no central står, in which case they 

 cannot be distinguished from C. Gigas. The most common form 

 resembles C. Gigas in the arrangement of its cellules, but C. Ocu- 

 lus Iridis in the central står of larger cellules. Probably C. Oculus 

 Iridis, Gigas and radiatus are only varieties of one and the 

 same species. The size of the marginal cellules of C. Gigas 

 from the Virginia deposit ware found to be 4 cells in O, o 2.0 m.m. 



2. Coscinodiscus lineatus Ehrb. (Kg. Bac. Pl. I fig. 10) var., 

 excentricus (C. eaxentricus Auct.) not very rare. 



Coscinodiscus lineatus and excentricus are connected by sa 

 many intermediate forms, that they can hardly be different spe- 

 cies. The specimens of that species were surrounded by a large 

 limbus of mucus, divided into segments by radiate lines, pro- 

 bably a secretion from the joint of the two valves. The case 

 reminds one of C. Sol. Wallich (accord. to Pritch. Infus.). 



3. Coscinodiscus concavus Greg (Diat. of Clyde pag. 500 

 Pl. X fig. 47 non C. concavus Ehb. ^ Endictya oceania). Disc 

 covered by regular, somewhat large, hexagonal cellules (6 in 

 •0,0 2 5 m.m.) arranged in straight lines niaking with each other 

 en angle of 60°. Diam. 0,0 5 m.m. Colour of the dry valve 

 leaden. 



This species, which was somewhat rare in the diatomaceou& 

 raass from Java, cannot be the same as Endictya oceania, which 

 I have seen from Peruvian guano. In most specimens of C. con- 

 cavus four mucous masses were projecting from the joint of the 

 two valves. 



