118 Palaeontolo^ie. — Algae. 



fragments contained in the State Herbarium. New species founded 

 upon structural materials are described in Sigillaria and Araucari- 

 oxylon. From the forest bed beneath the Kasan drift the author 

 records and figures cones of Picea mariana (Mill) B.S.P. and wood 

 showing structure of Picea canadensis (Mill) B.S.P. Berr3^ 



White, D., Permo-carboniferous climatic changes in 

 South America. (Journ. of Geol. XV. p. 615—633. 1907.) 



Chiefly a climatic study based on the fossil plants coUected by 

 the Goal Kommission of Brazil. These are definitely fixed stratigra- 

 phically and embrace a considerable vertical ränge. They show at 

 the extreme base of the Brazilian coal measures a pure Gangayno- 

 pteris (Lower Gondwana or Glossopteris) flora indicative of the cold 

 climate which succeeded the previousl}' uniform and equable cli- 

 mate which characterized the earlier Carboniferous in both the nor- 

 thern and the southern hemispheres. This was followed by sufifi- 

 ciently ameliorated conditions to permit the return of the hardier 

 I.ycopodiaceous types from the contemporaneous northern or „cos- 

 mopolitan" Permo-Carboniferous flora, and still later a restoration 

 of an equable Permian climate permitted the Immigration of other 

 northern pteridophytic types and the growth of gymnospermous 

 trees lacking annual rings. This return of an equable climate the 

 author believes to have taken place as earl}'^ in the Permian as the 

 beginning of the Damuda series of the Gondwana System or as 

 the early Zechstein of the northern S3\stem. With regard to the 

 cause of the widespread Permian glaciation in southern lands the 

 author believes that it can be explained by a depletion of the supply 

 of carbonic acid gas in the atmosphere due to its withdrawal in the 

 deposition of coal and limestone formations, combined with the 

 exaggerated temperature efifects due to the great increase in size 

 and elevation of southern land masses, the subsequent amelio- 

 ration being possibly due to subsidence under loading and a direct 

 contribution of carbon dioxide attending the great vulcanism of the 

 Permian. Berry. 



Börgesen, F., An ecological and systematic Account of 

 the Caiilerpas ofthe Danish West Indies. (Mem. Ac. roy. d. 

 Sc. et d. Lettr. de Danemark. Copenhague. 7™« Ser. Sect. d. Sc. 

 IV. 5. p. 337—392. 4». 1907.) 



In dem Jahren 1892, 1895—96 und 1905—6 hat Verf. Untersu- 

 chungen über die Algenflora der dänisch-westindischen Inseln vor- 

 genommen und teilt in der vorliegenden Abhandlung die Resultate 

 seiner eingehenden Studien über die westindischen Arten der Gat- 

 tung Caiderpa mit. 



In dem ersten Abschnitt giebt Verf. eine Darstellung der äusse- 

 ren Bedingungen unter welchen die Caulerpen leben. Diese Algen 

 sind nicht besonders biegungsfest oder zugfest konslruirt und wach- 

 sen deshalb nicht an Stellen, die den Wellen besonders expo- 

 niert sind. An weniger exponierten Lokalitäten oder in grösseren 

 Tiefen, wo die Wellen nicht so kräftig wirken können, kommen 

 aber die Caulerpen vielfach und in verschiedener Weise vor, wie 

 in dem zweiten Abschnitt näher auseinander gesetzt wird. 



Verf. teilt die Caulerpen in 3 biologischen Gruppen: 1) die epi- 

 phytischen und schlammsammelnden Caulerpen, für welche Can- 



