ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 801 



ments of Professor Morley were made with great care by means of a 

 Troughton and Sims micrometer belonging to the Hudson equatorial ; 

 the objective a Tolles ^L, and monochromatic sunlight was used ; 

 the measurements were afterwards carefully checked by J. E. Smith, 

 of Ashtabula, U.S., by the camera lucida, and they were found to 

 harmonize. 



The great discordance in the number of strife between the two 

 measurements is difficult to imderstand. We find in 



diiferent forms had been measui-ed, or that one of the systems adopted 

 was not to be depended upon. The former supposition seems the 

 more probable, as some of the measm'ements agree, or neaidy so ; 

 e.g. G. marina and Pleurosigma halticum, C. 14-5, M. 14 nearly. 

 Dr. Woodward * says the number of strife on Frustulia saxonica is 

 85-90 in '001 of an inch (31-36 in '01 mm.); Count Castracane 

 makes them 34 in • 01 mm. 



Dr. Schumann, in his ' Diatomeen der Hohen Tatra,' says he found 

 Navicula rhomhoides with strife as close as 78 in -j-i-g- Paris line ; this 

 is equivalent to 87f in • 001 of an inch, or 35^^ in • 01 mm. These 

 numbers agree very well with those on F. saxonica." 



Endophytic Algse.f — G. Klebs has made a careful examination of 

 a number of the lowest forms of algal life. The first part of his 

 paper has reference to two species belonging to the genus Cliloro- 

 clujtrium of Cohn, of which various forms have already been described 

 by Cohn, Kirchner, and E. P. Wright. 



CMorocliytrium Lemnce of Cohn was found, as indicated by that 

 writer, within the tissue of Lemna trisulca. The external form of 

 the single cell is very variable, spherical, elliptical, lobed, or 

 angular, and it is always found in the intercellular spaces of the 

 subepidermal parenchymatous layer of the upper or under side. 

 The cell-wall is moderately thick, consisting of cellulose, and 

 encloses a delicate green mass of protoplasm, with a few scattered 

 grains of starch and a large vacuole. As it developes, a number of 

 green threads of protoplasm are formed in the interior, which make a 

 beautiful network. Later it becomes filled with large starch-grains, 

 is denser, and assumes the appearance of a dajk green coarsely 

 granular mass. In this state it may remain for weeks, until the 

 period of formation of the zoospores, which is always the close of 

 the normal life-history. From the endojihytic character of the alga, 

 its great delicacy, and the dark colour and density of its contents, the 

 formation of the zoospores is very difficult to observe. The author 



* ' Lens,' i. p. 233. 



t Bot. Ztg,, xsxis. (ISSl) pp. 249-57, 265-72, 281-90, 297-308, 313-19, 329-36 

 (2 pis.). 



