ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
269 
this author did not exercise sufficient care in obtaining his material, 
and that his results are therefore unreliable. Clark’s statement that 
the follicular epithelium degenerates immediately after the escape of 
the egg, is quite inconsistent with JSobotta’s observations in the mouse. 
He objects also to Clark’s name of “ lutein cells,” and believes that 
the follicles described by Clark were in a state of atresia, and not 
normal at all. 
Eustachian Tube of Frog.* * * § ' — Dr. H. Spemann points out that the 
general opinion which homologises the Eustachian tube of Anura with 
the spiracle of Selacliii, cannot be said to be corroborated by embryo- 
logical investigations, such as those of Goette, Villy, and Gaupp. He 
has, therefore, re-investigated the subject. He describes in detail the 
development of the tuba (i.e. Tuba Eustachii + Cavum tympani) from 
the first visceral cleft, comparable to the spiracle of Selachii. In larval 
life it grows out into a long forward-directed strand, but the adult 
condition is phylogenetically more primitive, and the prevalent con- 
clusion as to the homology of the Eustachian tube is thus confirmed. 
Origin of Blood-corpuscles in the Lamprey .j — Herr Maurizio 
Ascoli has investigated this subject, both in the larva and adult of 
Petromyzon Planeri , with the view of determining the vexed question 
as to the origin of the red corpuscles. He finds that both in larva 
and in adult the leucocytes increase by mitotic division in the lymphoid 
tissue of the spiral fold, in the interstitial tissue of the kidney, and in 
the blood itself. Preparation of blood from larva and adult showed 
also that the red blood-corpuscles increase in the blood by the same 
process. The young erythrocytes could, however, at all stages be dis- 
tinguished from leucocytes, and there was no evidence to justify the 
hypothesis of Giglio-Tos that they arise from a special kind of leuco- 
cyte. The division of the erythrocytes in the blood itself is no doubt 
the primitive condition for vertebrates, and ceases to occur when special 
blood-making organs appear. 
egeneration and Ontogeny.j; — Prof. PI. Strasser made this the 
subject of a rectorial address. He compares the processes of growth 
in the two cases, and especially emphasises the importance of the 
environmental conditions as determining factors. He seeks to arbitrate 
between the opposed views of Weismann and Hertwig. 
b. Histolog-y. 
Chromoplasts and Chromioles.§ — Prof. Gustav Eisen proposes some 
new terms for nuclear structures found during his study of spermato- 
genesis in Batrachoseps attenuatus. In the nucleus of the spermato- 
gonium he finds minute chromatin granules for which he proposes the 
name of chromiole. 'These are strung on threads of linin, and are 
round and of uniform size. r Phe nucleus also contains two other struc- 
tures both described as nucleoli. The one of these is the true nucleolus, 
and sta ns like the linin granules; for it the name lininoplast is sug- 
* Zool. Jalirb., xi. (1898) pp. 389-116 (3 ply. and 2 figs.). 
+ Arch. Mikr. Anat., liii. (1899; pp. 623-31 (1 pi.). 
% ‘ Kegenevati >n mid Eutwicklung,’ Jena, 1899, 8vo, 31 pp. 
§ Biol. Central bl., xix, (1899) pp. 129-35 (5 figs.). 
