6 Crust. 
CRUSTACEA. 
1 . Nervous System and Organs of Sense. 
Notes on the brain of the Crustacea , by Packard, Am. Nat. xvi. 
pp. 588 & 589 ; abstract in J. R. Micr. Soc. (2) ii. p. 502. 
Microscopical researches on the nervous fibres and cells in the common 
crayfish, by S. Freud, SB. Ak. Wien, Ixxxv., Abth. 3, pp. 9-46. The cells 
consist, according to him, of two substances : one reticular, which is con- 
tinued into the fibrillas of the nerves ; and another homogeneous, which 
is continued into the interfibrillar substance of the nerves ; amoeboid 
bodies have been observed within the nucleus of the cells. 
Some observations on the physiology of the nervous system in the 
common crayfish, by E. Reiciienbach, Humboldt, i. pp. 26 & 27. 
The nervous system of Palcemoneles varians is described by A. 
Garbini, Atti Soc. Yen. Trent, vii. pp. 179-199, 6 pis. 
G. Bellonci describes the nervous system and the organs of sense of 
Sphceroma serratum (Latr.), Atti Acc. Rom. (3) x. pp. Sl-104, and also in 
Arch. Ital. Biol. i. pt. 2, pp. 176-192. He describes its external and 
microscopical structure, and comes to the conclusion that the brain of 
the Crustacea fully agrees morphologically with that of the Insecta ; 
the inner lobes of the uppermost part in the former are homologous 
to the mushroom-shaped bodies of the latter, the central reticular 
substance of the former to the fan-shaped part of the latter, the lateral 
protruding parts of the former to the olfactory lobes of the latter. The 
author further describes the hairs and other cuticular prominences 
which he assumes to be sensorial. The same author gives notes on the 
nervous system of Squilla mantis ; Rend. Acc. Bologn. 1881-82, p. 66, 
and M&n. Acc. Bologn. (4) iii. 2 pis. 
A. Fbic gives some notes on the structure and development of the ner- 
vous system in the Copopods; Zool. Anz. 1882, pp. 498-501. 
An unpaired eye, in addition to two compound eyes, is found in many 
Crustacea , and without the two latter iu the Copepoda and the nauplii- 
form larvae of all Orders ; it contains three lenticular bodies or crystalline 
spheres, each of which is composed of radiating elements or optical bacilli, 
the inner ends of which are applied against a pigmented mass, while the 
peripherical segments contain a nucleus ; the nerve, instead of penetrat- 
ing into the pigmented mass, skirts the outer surface of the crystalline 
sphere, and penetrates it directly. It may therefore be said to be com- 
posed of three simple eyes, with reversed optical bacilli, receiving con- 
ductive fibres of the optic nerve upon their outer margin. A nearly 
identical structure of the eye is found in the Chcetognatha and in some 
Planarians. M. Hartog, C. R. xciv. pp. 1430-1432 ; abstract in Ann. 
N. H. (5) x. pp. 70 & 71, Arch. Z. exper. x. pp. vii. & viii., J. R. Micr. Soc. 
(2) ii. p. 504, and Le Nat. 1882, No. 18, p. 138. 
Sir J. Lubbock’s observations concerning colour sense in Crustacea 
[Zool. Rec. xviii. Crust, p. 5] are also reported in J. R. Micr. Soc. (2) i. 
pp. 882-884. The author confirms by several experiments his state- 
ment that Daphnia is sensible to ultra-violet rays; J. L. S. xvi. 
pp. 121-127. 
