ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 125 



species, whicli are insufficiently described and figured, and wliich appear to 

 be the sole constant character by which the two species can be distinguished. 

 He confirms Dr. Braxton Hicks' statement of the development of a Ulotlirix 

 or ScMzogonium from a Pleurococcus. The radicles of U. radicans are 

 replaced in U. parietina by branches. 



Algse of Bohemia.* — In the first part of this important work. Dr. A. 

 Hansgirg treats of tbe general classification of Algte. Excluding tlie 

 Diatomacese, he adopts, in its main features, Eabenhorst's four classes of 

 Rhodophycese, Phseophyceee, Chloropbycese, and Cyanophycese. Under tbe 

 Phseophycese he includes the Syngeneticae [Ghromophyton and Hy drums), 

 nearly allied to which are the Phseozoosporese (Lithoderma). The Chloro- 

 phycese he divides into Confervoidese, Siphonese, Protococcoide^, and Con- 

 jugate. The oogamic Confervoidese are arranged under the families Coleo- 

 chsetace^e (Coleochsete and Herposteiron), ffidogoniaceas {(Edogonium and 

 Bulhochsete), and Sphteropleacese (Sphseroplea) ; the isogamous Confervace^e 

 under Ulvaceae (Prasiola, EnteromorpJia, and ScMzomeris), Chsetophoracese 

 (Ulothrix, Stigeoclonium, ChsetopJiora, and Draparnaldia), Cladophoracese 

 (Conferva, Bhizoclonium, and GladopJiora, and Trentepohliacese [Trentepohlia, 

 CJdorotylium, and Microihamnion). Botrydium he places under Siphoncfe. 



In a separate paper,! -D^"- Hansgirg enumerates the algae found in the 

 salt lakes and marshes of Bohemia. They are very numerous, and include 

 representatives of nearly all the forms of Chlorophycese ; but very few of 

 the species are peculiar to these localities. 



Structure of Diatoms. | — Mr, H. Morland supports the view that in 

 Navicula Durrandii the dots are nothing but minute perforations ; but he 

 cannot regard the median line or raphe as merely a thickening for 

 strengthening the valve generally ; he considers it, on the contrary, to be 

 simply a cleft with thickened borders. In this species he has sometimes 

 noticed, when examining the raphe, that it has two borders, in consequence 

 of the cleft being slightly oblique, one of which, under a higb power, will 

 be seen to be on the " upper " surface, while the other is on the " inner " 

 surface ; but if the ends of these borders be examined, it will be found that 

 they join each otber. The same is the case in Pleurosigma halticum. 



By the examination of carefully prepared sections of Jutland " cement- 

 stein," § Mr. Morland confirms Prinz and Van Ermengem's statements 

 with regard to the structure of the diatoms contained in it. The markings 

 on the diatom-valves are seen to be perforations, although the structure 

 differs in different forms. The author proceeds to describe the variations 

 found in Coscinodiscus oculus-iridis, Trinacria regina, Pyxidicula cruciata, 

 Stictodiscus Jeremianus, Arachnoidiscus Ehrenhergii, and Aulacodiscus mar- 

 garitaceiis. Of these he considers Trinacria regina to be one of the simplest, 

 while the structure of Aulacodiscus margaritaceus is highly complicated ; 

 but in all the markings are seen, if carefully examined, to be perforations. 



Xiiclienes. 



Soredial sporidia of Amphiloma murorum.|| — Sig. A. Borzi identifies 

 the gonidia of this common wall-lichen with Hormidium varium. He de- 

 scribes a peculiar mode of reproduction of the soredia which he observed in 

 very wet weather. Unicellular conidia from 2 to 4 /x in diameter were 



* Hansgirg. A., ' Prodromus der Algenflora von Bohmen,' Heft 1, Prag, 1886. See 

 Oesterr. Bot. Zeitschr., xxxvi. (1886) p. 313. 



t Oesterr. Bot. Zeitschr., xxxvi. (1886) pp. 331-6. 



X Journ. Quek. Micr. Club, ii. (1 886) pp. 297-307. § See infra. Microscopy /3. 



II Malpighia, i. (1886) pp. 20-4. 



