ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
61 
hitherto described among the Hydrachnidae, or, indeed, any of the allied 
families. The female genital organs, on the other hand, resemble what 
has been described by preceding writers. The so-called genital sucker 
has a formation entirely different from what would be expected in a 
sucker, and has much more the appearance of a sense-organ of some 
kind. In the histology of the great nerve-centre the principal point 
which attracted attention was the great thickness of the structureless 
neurilemma, below which is a single layer of the usual small round 
cortical cells coating the fibrous material of the brain, but this was 
much less conspicuous than is generally the case in Acarina. 
Stridulating-Qrgans of Scytodes.* — Mr. F. 0. Pickard-Cambridge 
has lately discovered the stridulating-organs in this genus. The struc- 
ture consists of a series of short transverse ridges. On the femoral joint 
of the palpus, near the inner basal angle, there is a stout conical pro- 
minence. This would, when the palpi were moved to and fro, pass over 
the ridges on the mandible, and perhaps produce a strident sound of 
greater or less intensity. 
e. Crustacea. 
Movements of Decapoda.f — Dr. Th. List has followed up his analysis 
of the crayfish’s movements by a study of other Decapods. He deals 
with Penseus caramote , Palsemon serratus , Leucifer, Sergesies, Nilca edulis, 
Homarus vulgaris , Palinurns vulgaris , Pagurus striatus , Pachygrajpsus mar- 
moratus, Portunus , Maja , &c. The study is most elaborate ; there are 
pages and pages of co-ordinate-tables and angle-tables, whereby those who 
wish may know how every joint of every leg of crab or shrimp or lobster 
moves. It is a monument to patience, but it seems to us to savour more 
of kinematics than of biology. 
Tertiary Decapoda.J — Sig. C. Crema has studied the Decapod Crus- 
taceans of Tertiary strata in Piedmont, and describes the following new 
forms : — Callianassa joedemontana , C. Povasendse, Lyreidus Paronse , Gono- 
jplax Sacci , G. (?) C raveni, and a number of others which have been pre- 
viously recorded or are incompletely defined. 
Breeding Habits of American Crayfish. § — Mr. E. A. Andrews has 
made a study of Cambarus ajjinis kept in confinement. He finds that 
conjugation takes place in the autumn and in the spring, and that it 
differs in many respects from what is known in Astacus. The peculiar 
organ of the female, the annulus, proves to be an essential, secondary 
sexual character. The male passes the sperm into the cavity of the 
annulus of the female, and does not distribute it elsewhere. The well- 
known hooks on the third walking legs serve to hold the two animals 
firmly together and are necessary secondary sexual organs. 
Glandular Cells of Anilocra mediterranea.il — Dr. O. vom Hath 
describes the minute structure of the remarkable (salivary or poisonous ?) 
glands on the head of this Isopod. What is most striking about these 
glands is the polycentric arrangement of the chromatin. Each of the 
* Ann. and Mag. Nat. Hist., xvi. (1895) pp. 371-3 (2 figs.), 
t MT. Zool. Stat. Neapel, xii. (1895) pp. 74-168 (3 pis. and 9 figs.), 
t Atti R. Accad. Sci. Torino, xxx. (1895) pp. G64-8i. 
§ Johns Hopkins Univ. Circ., xiv. (1895) p. 74. 
1| Zeitsclir. f. wiss. Zool., lx. (1895) pp. 1-89 (3 pis.). 
