INVERTEBEATA, CRYPTOGAMIAj MICROSCOPY, ETC. 679 



patches on stones, slaclls, &c. The thallus is formed of a single plate 

 of cells which increases by marginal growth. From this rise in a 

 vertical direction simjile or dichotomously branched filaments which 

 are enclosed in jelly and enveloped in a common cuticle. The tetra- 

 sporangia are developed on certain of these vertical filaments, branches 

 of which suspend their apical growth, the terminal cell developing into 

 a tetrasporangium. 



On tlje same plant are formed also the sexual organs, antheridia 

 and " procari)ia." The antheridia arc formed by rapid cell-multipli- 

 cation from the upper end of special filaments ; the procarpia in the 

 same way, the terminal cell of a filament developing into a long, slender 

 trichogyne. But in addition to these, procarjiia of a second kind are 

 also formed, in the shajje of short lateral 3-5-celled brandies on 

 numerous filaments of the thallus. The terminal cell of these lateral 

 branches, which always remain imbedded in the thallus, does not 

 develop into a trichogjnc, but retains the same form as the other 

 cells. After the trichogyne of the first kind of procarp has been fer- 

 tilized, a filament sjirings from its base, which branches and spreads 

 in the interior of the thallus, and there fertilizes a procarp of tlie 

 second kind by placing itself in apposition to one of its cells. Some 

 or all of the remaining cells of the procarp swell up in consequence, 

 and devcloj) spores. These chains of spores constitute the fructi- 

 fication of these Algae, to which Zanardini has given the name 

 " cystidia." 



In other species of Squamariea) examined, the process was the 

 same, indicating an analogy to that which occurs in Dudresnaya. 



Fresh-water Algse of Nova Zembla.* — The fresh-water Alga3 col- 

 lected in Nova Zembla by Dr. F. Kjollman are described by N. Wille 

 with the assistance of Professor Wittrock. The total number of 

 species is 172, belonging to 57 genera. Of Desmidieaj there are 

 100 species belonging to 13 genera ; the following new forms are 

 described and figured : — Oocystis (?) Novce. Semlice, Sorasirum (?) 

 simplex, Cosmarium pseudislli'mochondrum, subnofahile, KJellmani, and 

 Novce Scmlioi, Staurastriim KjeUmani and Novce Semlice, and Gonatozygon 

 Kjellmani. Microspora is united witli Confctva, and the mode of cell- 

 division in the latter genus minutely described. 



Thermal Anabsena.t — In the thermal spring known as Fontaine 

 chaude do Dax, at a temperature of 57^ C, II. Serres noticed an Alga 

 which lined the basin beneath the surface of the water, and wliicli lio 

 regards as Anahcena thrmalis. It originally develops as long, slender, 

 colourless, coherent filaments, which produce small, globular organic 

 bodies, singly or arranged in rows. The cylindrical filaments finally 

 become mouiliform and curved. The separate portions afterwards 

 develop into branches which may be Mmftiijochulus laminostis Cohn, 

 and which combine into a complicated network. Between tlic threads 



• Ofvera. af kougl. Vctensk-Aknd. Furli.' (1879), p. 13. Stc ' Bot. Ceiitmlbl.,' 

 i. (18S0) p. •^i,. 



t ' iJull. Sw. de Burdii li Dux,' v. (I8S0) p. i;i. Stc ' I!..t. rLiitrall.l./ i. (1S80) 

 p. 2:^7. 



