ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 059 



Multiplication of Nuclei in Striped Muscle of Vertebrates. * — 

 E. Godclewski, jun., has studied this in late embryos and recently born 

 young of guinea-pig and mouse, and in salamander larva?. Nuclear 

 multiplication takes place botb by direct and by indirect division. 

 Though previous observers have never announced the presence of 

 centrosomes in differentiated transversely striped muscle, the author 

 found them in typical form, not only in the monaster stage, but even 

 as early as the spirem stage. 



Structure of Hair-follicles.f — Dr. Adolfo Calef finds that in the 

 developing hairs of Mus decumanus var. albina the outer root-sheath 

 is furnished with an epithelial appendix, which is also seen, though less 

 markedly, in Sits scrofa. In the mouse the appendix becomes differ- 

 entiated into two regions, an upper which forms the sebaceous gland, 

 and a lower, separated by an incision, which lies at the side of the circular 

 zone of proliferation, already noted by Torri in developing human hairs. 

 Comparison with the adult mouse shows that the appendix corresponds 

 to the rudimentary accessory hair which often lies at the side of the true 

 hair. From a comparison with the pig and with the results of other 

 authors as to the zone of proliferation, Calef concludes that in all mammals 

 the oiiter root-sheath exhibits a more or less evident zone of proliferation 

 which is the point from which an accessory hair may originate, or simply 

 the rudiment of an atrophied hair ; it may possibly be the point from 

 which the first rudiment of the substitution-hair originates. 



Secretion in Amphibian Oviduct.! — V. Ellermann notes in frog 

 and newt the presence of granules as preliminary stages of the oviducal 

 mucus ; they occur on the threads of a plasmic network, aud show differ- 

 ential staining, c. g. with hajmatoxylin. The mucus occurs in the cells 

 in the form of large polyhedral bodies, and a complete series from the 

 minutest granules to these can be traced, especially in the newt. 



Intestine of Amia.§ — Mr. W. A. Hilton notes that the intestinal 

 convolutions are very complex in form and arrangement, being made up 

 of variously shaped folds and free projections or villi. There is a well- 

 developed outer longitudinal muscular coat and a very thick inner 

 muscular coat. Next the latter there is a thick connective-tissue 

 band, which scuds up projections of fibres into some folds and villi. A 

 muscularis mucosa is present, a few fibres of which are prolonged into 

 the cores of the folds and villi. The epithelium is simple, columnar, 

 and not ciliated, except for a small area towards the caudal end of the 

 spiral valve. 



New Edition of 'The Cell in Development and Inheritance; || — 

 Prof. E. B. Wilson has enlarged his valuable text-book by over a hundred 

 pages, and has added about fifty new figures. Some changes have DGen 

 made. It is recognised that the centrosomc is not always a permanent 

 cell-organ ; the alveolar theory of cytoplasmic structure is now more 



* Bull. Acad. Sci. Crncovie. 1900. See Amer. Nat., xxxiv. (1900) pp. 671-3. 

 t Anat. Anzcig.. xvii. (1900) pp. 509-17 (4 figs.). 

 I Op. cit.. xviii. (1900; pp. 182-9 (fi figs.). 

 § Amer. Nat., lxxxiv. (1900) pp. 717-35 (19 figs.). 



|| 'The Cell in Development and Inheritance,' bv E. B. Wilson, 2nd etl., Xew 

 York. 1900. xxi. and 483 pp., 194 figs. 



