ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 157 



hermaphroditism with testes and ovaries (with unpigmented ova), and 

 oviducts well formed, and two of effective hermaphroditism, able to 

 produce both eggs and sperms. There does not seem to be any direct 

 correlation between the state of the ovary and the degree of development 

 of the oviduct. Bidder's organ has doubtless come to have a secondary 

 physiological significance, but it is morphologically a rudimentary ovary. 



Eggs of Skates.* — A, Chas. Williamson has done a useful piece of 

 work in preparing drawings of the egg-cases or mermaid's purses of 

 seven species of skate, showing that these have in some cases a marked 

 specificity. 



Spermatozoon of Guillemot-! — E. Ballowitz describes the mature 

 spermatozoon of Uria lomvia, which shows (a) an elongated cylindrical 

 curved head with an apical piece ; (b) a middle piece with a spiral 

 filament coiled around the axis ; and (c) the tail ending in a short fine 

 terminal portion. 



t 



Larval Phases of Nemichthydas.J — Louis Roule finds evidence 

 that the forms described as Tilurella are larval stages of Nemichthys, 

 the principal genus in the family Nernichthydas. In this family, there- 

 fore, as in other Apoda, the occurrence of Leptocephalid or Lepto- 

 cephalid-like larvae is characteristic. 



b. Histolog-y. 



Active Movements of Epithelial Cells.§ — A. Oppel describes the 

 active movements of the epithelial cells at the wound-surface of a tail 

 excised from a tadpole. Apart from a passive shifting of cells as the 

 result of pressure, there is independent movement. This is to be seen 

 also when half of an excised cornea has the epithelium stripped off it. 

 The epithelial cells on the uninjured half elongate, and some of them 

 move on to the stripped half. 



Miiller's Epithelium. || — S. E. Wichmann maintains the homology 

 of the Mullerian duct in mammals, reptiles and amphibians, and 

 describes its origin from a flat stretch of blastema, which is phylo- 

 genetically derivable from the nephrostomial epithelium of the pro- 

 nephros. He gives the name " Miiller's epithelium " to the various 

 components of this blastema and to the epithelium of structures which 

 arise from it, such as Miiller's duct and the fimbria ovarica. 



Muscle-bands in Middle Coat of Arteries. f — A. H. MacCordick 

 finds that when the course of an artery is straight, and it is not sub- 

 jected to bending, the muscle-fibres of its media are circularly disposed. 



* Sci. Invest. Fisheries Scotland, 1912 (published 1913) No. 1, pp. 1-6 (5 pis.), 

 t Anat. Anzeig., xliv. (1913) pp. 305-9 (9 figs.). 

 X Comptes Rendus, clviii. (1914) pp. 352-4. 

 § Anat. Anzeig., xlv. (1913) pp. 173-85 (7 figs.). 



|| Verh. Anat. Ges., 1913, in Anat. Anzeig., xliv. (1913) Erganzung., pp. 139-54 

 (19 figs.). U Anat. Anzeig., xliv. (1913) pp. 225-61 (3 figs.). 



April 15th, 191 If. M 



