102 SUMMARY OF CURRENT RESEARCHES RELATING TO 



tlircc liimcllic. This pcriniiim is also present in other Hepaticro, as 

 Hiccia, in Marchautia, Atithoceros, some mosses, Osmunda, Equiseium, 

 and LiicopOiVnim, being sometimes known as the exospore, sometimes 

 as the cuticle. It always results from metamorphosis of the inner- 

 most portion of the membrane of the special mother-cell of the 

 spores. 



In the germination of these spores both perinium and extino arc 

 ruptured by the swelling of the iutine, which forces its way through 

 them as the first rhizoid. The germinating tube is inclosed in tlio 

 intinc; in Sphcerocarpus it does not break through the extine, but 

 stretches it so greatly that it passes over immediately into the cuticle ; 

 while in Echoulia it bursts through it. Leitgcb does not find in the 

 Hepatica) examined any new formation of an additional inner layer of 

 the membrane during germination. The function of the euticularized 

 extine appears to be to protect the spore against too rapid loss or 

 access of water. The perinium, on the other hand, is permeable to 

 air and water ; its chief purpose appears to be to serve as a protection 

 against the attacks of fungi. 



Algae. 



Florideae of the Mediterranean.* — The first part of F. Ardissone's 

 ' Phycologia Mediterranca ' is devoted to the Floridefe, the genera 

 and species of which arc worked out and described with very great 

 care and minuteness. Ardissone divides the Mediterranean into 

 three zones of depth : the first from the surface to 5 m. ; the second 

 from 5 to 35 m. ; and the third dowTi to the lowest limits of algal 

 vegetation. The uppermost of these is again divided into three sub- 

 zones; and all these zones and sub-zones have their peculiar and 

 characteristic vegetation. 



As to general results, it may be stated that the Mediterranean is 

 especially rich in Bryopsidese ; then come the Halymeniete, Cystosirea;, 

 and Ceramiacea) ; Laminariaceae and Fucacete are only sparsely 

 represented, as also the Caulerpeae. Excluding diatoms, the algal flora 

 of the Mediterranean amounts to about 600 species, of which about 

 one-half are at present not known elsewhere. 



The classification of the Florideae adopted is nearly that of Agardh, 

 viz. into 6 families: — (1) Gongylospermeae, including Ceramiaceae 

 and Cryptomeniacepe ; (2) Coccospcrmese, including Gigartinere 

 only ; (3) NematospermecTe, including Dudresnaiaceae, Spiridiacene, and 

 EhodymeniacetG ; (4) Hormosjiermcfe, including Squamariacete, 

 Sphterococcefe, and Delesseriaceae ; (5) Desmiospermea), including 

 Helminthocladaccfe, Hypneacefe, and Gelidiacete ; and (G) Coryno- 

 spermeaj, including Wrangeliaceae, GastrocloniaceaB, LaurenciaceaB, 

 Ehodomelaceie, and Coralliuaceae. 



Occurrence of Chromatophores in the Phycochromaceaet— G. 

 Lagerheim describes distinct chromatophores in a phycochromaceous 

 alofa Glaucocystis Nostochincarum, nearly allied to the palmellaceous 

 genus Oocystis, but differing in the nearly blue cell-contents. In the 



* Mein. Soc. Crittogam. Ital., i. (1883) .'ilG pp. 



t Bcr. Deulsch. Bot. Gcscll., ii.(1884) pp. 3u2-4 (3 figs.). 



