250 The Microscope. 



increased to many times its original bulk. The eggs then become 

 separated and form an inner spiral chain. Slightly magnified, the 

 egg-case appears divided into many equal segments by narrow 

 transparent rings; and two transparent threads, twisted with each 

 other, may be traced from " the neighborhood of the lower to the 

 upper extremity, where they unite and are continued beyond as a 

 single thread terminating in an adhesive disk. The eggs appear 

 somewhat oval in form, and are arranged in a spiral which shirks a 

 complete turn, and when all but round, makes a loop and goes back 

 again. The nearly completed rings thus formed lie each within a ■ 

 separate segment." 



Muscles of Molluscs. — There are frequently described in 

 molluscs striated muscles, sometimes of a peculiar type. Miiller and 

 Keferstein have described them in the hparts of Cephalopods and in 

 the pharynx of the Cephalophora ; Blanchard in the adductors of 

 Pecten, and Paneth in the fins of Pteropods and Heterapoda. 

 Schnalbe has described in the adductors of the lamellibranchs and 

 elsewhere muscles with a double-oblique striation, while, before 

 him, Mettenheimer, Wagener and Margo had referred to the same 

 appearance as spiral striation. Lately, Fol {Comptes Rendus, 

 January, 1888), has investigated the same subject, and concludes 

 that true striated muscles do not exist in any mollusc. All cases 

 reported as such, in reality consist of smooth fibers, around which 

 fine fibrils are rolled in a spiral manner, this being the case in all the 

 special instances noted above. The method employed by Paneth 

 (glycerin and nitric acid) produced such contraction that the spiral 

 fibrillse really appeared transverse. All of the molluscan muscles 

 are of the smooth type ; but these are to be groaped in two subdi- 

 visions — that already mentioned, and that in which the fibrillse are 

 straight. The latter are the more abundant. Judging fi'om their 

 distribution, the spiral type are of value where a rapid contraction is 

 needed. — American Naturalist. 



Tupelo Wood in Section Cutting. — A correspondent of The 

 Microscopical Bulletin writes : I see from one of the pharmaceuti- 

 cal journals, that a German microscopist recommends tupelo wood 

 [Nyssa candicans, niichix, etc.) for use in section-cutting, which 

 grows in the Southern United States, not far from the sea coast. It 

 is stated to be superior in several respects to elder pith, sunflower 

 pith and cork. In hardness the wood is intermediate between elder 

 pith and cork. 



