198 
Conspectus Criticus, Diatomacearum Danicarum. By Dr. 
Puiu, P. A. C. Herperc. Copenhagen, 1863. 
Turis work, which is, unfortunately for its ready perusal, 
written in the Danish language, professes to give a general 
review of the Danish species of diatoms. 
It commences with a general account of the natural history 
and structure of these organisms, and with a definition of the 
terms employed in their description, in which, so far as we 
are able to make it out, there does not appear to be anything 
new, though it contains a good deal of useful historical infor- 
mation with respect to the species noticed by Otto Miiller, 
Lyngbye, and other Danish writers. 
The second part is systematic, and the following table will 
serve to show the arrangement followed by the author in the 
classification of Danish diatoms : 
J. Valves equal (eensdannede). 
A. “Front view ” symmetrical in the longitudinal axis. 
(a) “ Side view ” circular. 
Fam. 1. MrLosirnez, Grunow. 
1. Melosira, Ag. 
2. Lysigonium, Link. 
3. Orthosira, Thwaites. 
4. Paralia, n. gen. 
(5.) Pyxidicula, Ehy. 
(6.) Coscinodiscus, Ehy. 
7. Actinocyclus, Ehr. 
8. Eupodiscus, Ehr. 
9. Auliscus, Ehr. 
(b.) “Side view ” not circular. 
a. “ Side view” symmetrical longitudinally. 
Fam, 2, BippuLPruie#, Kutz. 
Tribus 1. Biddulphiee genuine. 
10. Cerataulus, Ehr. 
11. Biddulphia, Gray. 
12. Triceratium, Ehr. 
13. Amphitetras, Ehy. 
