ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
71 
place after sundown. A comparative study of the eyes of Epliemerids 
shows that it is possible to construct a series illustrating the evolution 
of these complex frontal eyes. 
The point of interest is the similarity in structure to the eyes of 
deep-sea Crustacea, where the modified eyes enable the possessor to 
seize active prey. 
Male Genital Organs of Hydrophilus.* — P. Blatter gives a detailed 
description of the male genital organs of this beetle, — the testes, the 
efferent ducts with seminal vesicles, and the glandular accessory organs. 
The system is highly differentiated ; but like that of other Coleoptera, it 
conforms in essentials to the general plan which Escherich worked out 
in the Carabicidre. A useful comparative table may be reprinted. 
Carabus. 
maps. 
/ 1. Efferent canals, 
1. Efferent canals. 
! i. 
acting as semi- 
Organs 
nal vesicles at 
arising 
the base. 
from 
2. Accessory glands 
! 2. 
the 1 
(mesadeniae) opening 
meso- 
into the base of (1). 
derm 
3. 
Organs 
A 1. Penis. 
1. Penis. 
1. 
arising 
j 2. Genital armature. 
j 2. Genital armature. 
2. 
from 
; 3. Ejaculatory duct. 
3. Ejaculatory duct. 
3. 
the { 
4. Tubular accessory 
4. Scorpioid glands 
4. 
ecto- 
glands (ectade- 
(ectadeniae). 
derm 
v niae). 
Hydrophilus. 
Efferent canals. 
Seminal vesicles. 
Accessory glands 
(mesadeniae) forming 
a 3-branclied tube. 
Penis. 
Genital armature. 
Ejaculatory duct. 
Chalk-white accessory 
glands (ectadeniae). 
Genital Ducts of Calliphora.f — Dr. L. Briiel has made an exhaust- 
ive study of the anatomy and development of the genital ducts and the 
associated organs in Calliphora erytlirocejphala. His results show that 
these are of ectodermal origin, and render it at least probable that this 
is also true of some, if not all, of the Diptera, Hymenoptera, and 
Hemiptera. In an additional note, the author criticises the work of 
B. Thompson Lowne on the Blow-fly. 
Formation of Sex-Cells in the Silk-Moth, t — Herr v. la Yalette St. 
George discusses this subject, giving an account of some observations of 
his own. In 1889 Yerson described the four spermatic tubes in Bornbyx 
mori. He found at the apex of each tube a very large cell, with an 
eccentric nucleus containing little chromatin, and stated that this cell 
is produced by amitotic division daughter-cells, which ultimately become 
the spermatozoa. These remarkable results were discussed by Yerson 
himself and others in numerous later papers. Toyama, who especially 
investigated the subject, found Yerson’s cells in the ovary as well as in 
the testes, and believed that they were supporting cells which had 
* Arch. d’Anat. Micr., i. (1897) pp. 384-416 (1 pi. and 3 figs.), 
t Zool. Jahrb., x. (1897) pp. 511-618 (3 pis.). 
J Arch. Mikr. Anat., 1. (1897) pp. 751-66 (3 pis.). 
