ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 453 



Cavernicolous Myriopods.* — F. Silvestri describes from the eastern 

 region of the Pyrenees (a) two new Diplopoda— Spelmor/lomeris docleroi 

 g. et sp. n. and Sp. racovitzw sp. n., and (b) a new centipede, Lithobius 

 allot 'yphlus. 



8. Arachnida. 



Cave Pseudoscorpionidae.f — Edr. Ellingsen reports on a dozen false 

 scorpions from Pyrenean and other caves, including Obisium lonijidigi- 

 tatum sp. n., and a new blind variety of Chthonius tetrachelatus. It 

 should be noted that some of the dozen species discussed are only acci- 

 dentally cavernicolous. 



f, Crustacea. 



Stridulating Organ in Crabs. % — W. T. Caiman describes a well- 

 developed stridulating organ in males of an African river-crab, Potamon 

 (Potamonautes) africanum. It is formed by groups of modified spines 

 on the upper surface of the coxa? of the first and second pairs of walking 

 legs, and on parts of the free branchiostegal edge of the carapace imme- 

 diately opposed to them. The organ occurs in some other species of 

 this genus, but it is not known in other genera of Potoinonidse. 

 Stridulation, or the possession of apparently stridulating organs, has 

 been reported in Matuta, Ozius, Platyonychus, Ocypode, Macroph- 

 thalmus, Sesarma, and some other Clrapsidaj, but in these cases the main 

 portion of the apparatus consists of ridges or granules on the surface of 

 the exoskeleton, never of modified spines, although the latter are 

 commonly found in the stridulating organs of the Arachnida. 



Hydrotropism in Crabs. § — Anna Drzewina has studied the be- 

 haviour of shore crabs {Carcinus mamas) when taken away from the 

 sea. Even at a distance of over 100 m. they make for the water. This 

 is independent of illumination, time of day, wind, etc. The crabs may 

 ascend inclined planes in making for the sea. They are hydrotropic. 

 When the sand is very wet with rain they do not go straight for the sea. 

 They walk along a bar with water on each side of them, as if equally 

 attracted in the two directions. Crabs that live near high-tide mark 

 are very much more sensitive hydrotropically than those from low-tide 

 mark. Experience counts. In investigating reactions the past of the 

 animal must be borne in mind. Crabs taken from the wrack-covered 

 rocks of the seaweed zone make for rocks and sea-weed patches rather 

 than for the sea. 



Visceral Nervous System of Decapods. || — G. Police has studied 

 this in Palinurus, Homarus, Astacus, Scyllarus, Penceus, Galathea, Maja, 

 Dromia, Carcinus, and other Decapod Crustacea. The anterior portion 

 of the visceral nervous system includes two lateral centres (the paired 

 visceral ganglia) and an unpaired median ganglion. The relations of 



* Arch. Zool. Exper., via. (190S) Notes et Revue, No. 3, pp. lxv.-lxxiii. (14 figs.). 



t Tom. cit., pp. 415-20. 



% Ann. Nat. Hist., series 8, i. (1908) pp. 469-73 (5 figs.). 



§ C.R. Soc. Biol. Paris, lxiv. (1908) pp. 1009-11. 



|| MT. Zool. Stat. Neapel.xix. (1908) pp. 69-116 (2 pis. and 1 fig.). 



