238 SUMMARY OF CURRENT RESEARCHES RELATING TO 



the spermatozoa arise by true scgmeutation of the niotlicr-cclls is 

 iucorroct, aud that it arises rather by direct genesis in tlic protoplasm 

 of the protospenaatobhist, and that it is, therefore, the liomoh)gne of 

 the corpuscles which appear in the yolk of the egg and form the 

 follicular cells. In fine, it obeys the laws already enunciated by 

 Sabatier, 



Development of the Egg and Formation of the Primitive layers 

 in Cuma Rathkii.*— H. Blanc in this paper seeks to establish an 

 affinity between the development of the Cumacese and that of certain 

 Isopoda, Oniscus amongst others. 



Brain of Asellus and Cecidotaea.f — A. S. Packard has studied the 

 structure of the brain and organs of sight of Asclhis communis, a.nA 

 compared it with that of the same parts in the blind Cecidotcea stygia. 

 The latter in its external form is a somewhat dwarfed AscUus, and 

 is not usually totally eyeless, since in some individuals a rudimentary 

 eye, in the shape of a minute black speck, is seen on each side of the 

 head. Cecidotcca differs from Asellus in the complete loss of tho 

 optic ganglia and nerves, besides the sometimes nearly total loss 

 of the pigment-cells and lenses. As regards the other parts of 

 the brain, no differences were observed. The steps taken in the 

 degeneration or degi-adation of the eyes seem to be (1) the total and 

 nearly or quite simultaneous loss by disuse of the optic ganglia and 

 nerves, (2) the breaking down of the retinal cells, (3) the disappear- 

 ance of the lens and retina. These modifications are due to (a) 

 change in the environment, and (h) heredity. 



Deep Fauna of Swiss Lakes.+ — F, A. Forel enumerates the 

 works of previous writers on this subject, and corrects the facts and 

 theories which he had previously advanced on tho origin of the blind 

 Gammams and Asdlns of the deep parts of lakes. Formerly he 

 attributed them to direct emigration from a littoral fauna, which, 

 penetrating into a region devoid of light, had there lost the visual 

 organ and pigment ; new researches, however, now lead him to con- 

 clude that these blind Crustacea are descended from cave-inhabiting 

 animals, which had already become differentiated in the dark sub- 

 terranean waters. 



New Amphipodous Crustacean.§ — T. E. E. Stebbing describes 

 under the name of Cyproidia damoroniensis a new amphipodous crus- 

 tacean collected at Straight Point, Devon. The mounted specimens 

 are red in some parts and purple in others, the size, 1/10 in., agreeing 

 with the diminutive proportions of the other species of this curious 

 genus. 



Crustacean inhabiting the Tubes of Vermilia.|l — W. A. Haswell 

 describes a new crustacean which he found inhabiting tubes of 

 Vermilia (SerpuUdce), and names Eisothistos vermiformts. In some 



* Arcli. Sci. Phys. et Nat., xii. (1S84) pp. 430-2. 



t Amer. Natural., xix. (1885) pp. 85-6^ 



X Arcli. Sci. Phys. et Nat., xii. (1884) pp. 444-5. 



§ Ann. and Mag. Nat. Hist., Ixxxv. (1885) pp. 59-G2 (1 pi.). 



II Proc. Linn. Soc. N. S. Wales, ix. (1884) pp. G76-80 (2 pis.). 



