18 Crust. 
CRUSTACEA. 
immature male form. B. pelagica , Spence Bate, must be considered as the 
female of the same species. 
Bouvier (5, G) compares the structure of Dromia with that of more 
normal Brachyura , with special reference to the vascular system. 
Pouchet (1) has found females of Dias longiremis infested throughout 
almost all the spaces of the body by parasitic masses of granular proto- 
plasm which, when passed out at the anus, develop into active biflagellate 
forms. 
Sars (1) gives a minute account, with anatomical drawings of the 
larval stages, of the following species of the Crangonidce : — 
Crangon vulgaris, C. allmanni. 
Cheraphilus echinulatus , C. nanus. 
Pontophilus spinosus, P. norvegicus. 
Sabinea septemcarinata. 
Sclerocrangon boreas. 
Habits . 
Newly-hatched Nauplii of Balanus seek the light, or are positively 
heliotropic, when the light is subdued. If the light is strong, they 
become negatively heliotropic. Both ends of the spectrum are effective, 
but the violet rays exercise the stronger influence. The tendency towards 
migration is not inherent, since it does not take place while the light is 
constant. These facts serve to explain the daily migration, to and from 
the surface, of pelagic fauna. Groom & Loeb. 
Thompson (1) finds the use of the electric light very valuable in 
drawing rare species of minute Crustaceans from their retreats. 
See also Sterry, Hargitt, Herdmann, Holt, Weiss. 
Sense Organs . 
An examination of the eyes of Cambarus setosus, a blind Crayfish from 
the caves of Missouri, and of C. pellucidus , from the Mammoth Cave, 
establishes the presence of an optic ganglion and nerve in both species. 
C. pellucidus presents more distinct retinal traces. Parker, S. H. (2). 
Beddard (1) continues his researches on the structure of the eye of 
Isopoda. [See Zool. Rec. xxv, Crust. , Beddard.] The type now 
discussed is Arcturus. The shallow water forms {A. furcatus , A. ameri- 
canus, A. studeri ) have clear and transparent lenses. In some of the deep 
water forms an opacity in the lens is apparent. In others the lens is 
reduced in size and altered in shape. The retinula cells are small, a pos- 
sible indication of degeneration, while the rhabdom is relatively large in 
the deep sea forms. 
Respiratory Organs and Appendages. 
Bouvier (1) finds that the blood distributed by the a ntennary arteries 
to the carapace of Becapoda does not pass to the gills, but is returned 
