86 



HARDWICKE'S SCIENCE-GOSSIP. 



Rabenhorst) ; spirals wider than in the foregoing, 

 4-5 /x high ; each cell for the most part embracing 

 only Jon, seldom I J to 2 or 3 spirals ; a fkgellum 

 at each end. Very actively motile, at times also 

 forming a zooglcea. 



In bog-water and various infusions. 



Ehrenberg gives for .9. tenue a thickness of xunn °f a ' me > f° r 

 •S". Undula only -^Sn °f a ' me i at tne same tlme ne sa y s ' n tne 

 •description : " Sp. fibris valde torulosis brevibus, validioribus." 



According to Warming -S". Undula is more variable than was 

 formerly admitted. The spir.ds are often elongated, so that the 

 cell appears almost straight; accordingly the height of the 

 spirals varies from 3 to io'5 fi, the diameter amounts to J or j£ 

 of the height, the thickness of the cells "6-X*3 n. 



Var. lit or ale, Warming. 

 As much as 3 /x thick, spirals elongated, each 5 _I ° 

 jx high, diameter | or J of the height. 

 On the shores of the Baltic Sea. 



62. S. volutans, Ehbg. 



Vibrio Spirillum , M idler. 

 Melanella Spirillum, Bory. 

 Cells slightly attenuated towards the ends, gently 

 rounded, 25-30 /x long, about I5-2 xi thick ; each 

 cell with 2^-33 (seldom more) spirals, the spiral 

 9-13 ju high, 65 /x in diameter; a flagellum at each 

 end. 



In various infusions, as well as in bog-water among 

 algae. 



According to Warming the spirals are often elongated, so 

 that the cell appears almost straight ; the diameter then amounts 

 to only 1 "5-4 n. 



Var. robustum, Warming. 



Thickness 2-4/5 Mi height of the spirals 10-20 11, 

 diameter 1-3 jx. Usually with I J turns. Sometimes 

 with two flagella at one end. 



In sea-water. 



63. S. sanguineum (Ehbg.), Colin. 



Ophidomonas sanguined, Ehbg.* 



Cells cylindrical, only seldom attenuated at the 

 ends, 3 ll or more thick, of various lengths, with 

 usually 2, seldom h or 2\ spirals. Height of the 

 spirals 9-12 tt, diameter about § of the height ; a 

 flagellum at each end. Cell-contents coloured by 

 numerous reddish bodies, with many sulphur 

 granules. 



In putrefying brackish water [and pond water ?] 



According to Warming the longest specimens reach 65 /x ; the 

 height of the spirals 15-37 Mt while the diameter amounts to J 

 or 3, or in small specimens j— ^ of the height. 



64. S. violaceum, Warming. 



Cells either crescent-shaped (and so without a 

 complete turn) or with I or I; spirals, broadly 

 rounded at the ends, with a flagellum at each. Cell- 

 contents violet, with few sulphur granules. Height 

 of the spirals 8-10 it, diameter 1— 1 *5 it, thickness of 

 the cells 3-4 fx. 



In brackish water. 



* According to Saville Kent, the Ophidomonas sanguinea of 

 Ehrenberg is a true monad, and not identical with Cohn's 

 Spirillum sanguineum. See " Manual." — Tr. 



65. S. Rosenbergii, Warming. 



Cells with 1 or \\ turns, 4-12 it long, 1*5-2 '6 /x 

 thick, colourless, but with extremely numerous 

 strongly refringent sulphur granules. Spirals 6-7J 11 

 high, of very varied diameter, which amounts at the 

 most to half of the height. Moving actively and in 

 the most varied fashion, but, as it seems, without 

 flagella. 



In brackish water. 



66. S. attenuatum, Warming. 



Cells strongly attenuated at the ends, usually with 

 3 spirals. The middle spiral is large and close 

 (height about 11 it, diameter 6 11), the end spirals are 

 elongated (10 it high, 2 it in diameter). Thickness 

 of the cells 2 or 1 *2 it. 



In sea-water. 



67. S. Jencnsc (Ehbg.)* 



Ophidomonas jfenensis, Ehbg. 

 Cells obtuse at both ends, with flagella, olive- 

 brown, 40 [x long, about 3], fx thick, with \-z\ 

 spirals. 



Whether this is really a distinct species is hard to say, so 

 long as it is not found again in the original locality. Possibly 

 it is identical with S. volutans. 



W. B. Grove, B.A. 

 {To be continued.) 



THE DANISH FOREST. 

 By John Wager. 



III. — The Distribution of the Wild- 

 Growing Trees. 



IN Denmark, as in other countries, most of the 

 different species of wild-growing trees have 

 their different localities, in which the one species 

 affecting the soil, or acted upon by other circum- 

 stances, prevails more than another ; while some 

 species may even be almost or altogether absent from 

 certain tracts. Dr. Vaupell devotes a long chapter 

 to this subject, which is here compressed into more 

 limited space. 



Beech is at home on a calcareous soil, and grows 

 best on argillaceous sandy marl, the prevailing soil 

 of nearly all the fertile parts of Denmark. Yet it 

 grows also on heavy clay, and is the predominant 

 tree on all wooded boulder-sand. The growth of 

 the beech on such soil is peculiar to Denmark, and is 

 dependent on the preparation which other trees, 

 previously growing upon it, have made ; planters 

 well knowing that on first planting such sand-hills 

 they must not begin with the beech — spruce being 

 usually chosen, though Scotch fir would be better. 

 Beech-woods avoid swampy grounds and peat-mosses, 



• Saville Kent classes this as a true monad. See " Manual." 

 I -Tk. 



