Diatomacese from the Caspian Sea. By A. Grunow. G85 



He does not notice its presence in the Para mud, where it is not 

 very rare ; this perhaps throws suspicion on the identity of the two 

 species. He, however, notices another form, which he thinks is a 

 var. of his C. pulchella (which he says is perhaps the same as 

 stylorum), "and well deserves the name" (l. c. p. 348). 



In the work just above quoted is a figure of what he calls G. 

 Kutzingiana var, and which he describes thus : " The central por- 

 tion is large, elevated, and irregularly punctate ; the striae are minute 

 and closely radiant, reaching the margin, but interruj)ted before 

 reaching the margin by a finely undulate circle." His figure very 

 much resembles that of C. Casjn'a ; the centre is, however, larger 

 and more finely punctate ; it is also very like the small valves of 

 G. stylorum. 



G. compta Ehr. has a resemblance to G. Meneghiniana Kg., 

 but difi'ers in its more strongly granulate centre, and that every 

 second, third, or fourth marginal stria is stouter than the others. 



G. Meneghiniana Kg. is identical with G. rectangulata Breb., and 

 like G. Gasjna, has no marginal spine, but a more strongly striated 

 margin (7 to 9 delicately punctate stiiae in ' 1 mm.). G. Kutz- 

 ingiana W. Sm. appears to be the same species. 



G. Kutzingiana (Ehr. ?) Chauvin, has, according to original 

 examples from Chauvin, likewise no marginal spines, but a very 

 delicately striate margin (llJ-ll in "Ol mm.). C. Gaspia perhaps 

 might be considered a very delicately striate form of this species. 

 In kieselguhr from Domblitten is found a very interesting form 

 with an oval centre and 14-15 marginal striae in -01 mm. This 

 I consider a var. ? of G. Schumanni. 



The remaining species of Cyclotella is Discoplea grasca 

 (Ehr. ?) Schumann ; D. umlilicata (Ehr. ?) Schumann, and D. 

 hipunetata Schumann seem to be of similar structure. Most of 

 Ehrenberg's species are unrecognizable. 



G. scotica Kiitz. appears, according to the original examples 

 from Constantinople (query, identical with the Scottish form?), to 

 be no Cyclotella, but a Podosira ; the entire valve is very delicately 

 and irregularly punctate, and beset with a single circlet of stout 

 spines. 



Discoplea annuJata Schumann seems to be allied to Melosira 

 Westii, and D. umbilieata Ehr. to be identical with the latter. 



Gydotella hella A. Schmidt. — This is perhaps a Stephanodiscus, 

 or may belong to the genus Coscinodiscus. The same applies to 

 G. punctata W. Sm., G. Astrsea and minutula Kg. (these two 

 appear to merge completely into each other). G. Garconensis 

 Eulenstein does not belong to G. Astrxa as Eulenstein con- 

 sidered, but is a good species, characterized by the smooth radiating 

 lines starting from the intramarginal spines, and which pass 

 through the radiant puncta. G. spinosa Schumann is identical 



VOL. II. 2 z 



