ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 609 



The outer blade of the jaw has one accessory tooth ; the inner blade 

 has also one, followed by a diastema and a row of 10 or 11 denticles. 



5. Arachnida. 



Copulation in Spiders.* — Fr. Dakl found that out of sixty female 

 •spiders belonging to the genus Latrodectus eight bore broken-off male 

 copulatory organs. The long ribbon-like " embolus " of the male Latro- 

 dectus 13-guttatus is inserted at the vulva, not directly into the recepta- 

 culum seminis, but into one of two spirally coiled tubes which lie 

 beside it. Through these there is a curiously circuitous way to the 

 Teceptacula, perhaps adapted to prevent hybrid-fertilisation. A broken- 

 off embolus was found in at least three species of Latrodectus. A re- 

 vision of the species is appended. 



Living Hydrachnid Larvae in Trout's Stomach. f — C. D. Soar calls 

 attention to an interesting case. In the course of the investigations 

 carried out by the " Lake Survey " under Sir John Murray, a trout was 

 taken from Loch Eannoch, in the stomach of which Dr. T. N. Johnston 

 found living larva? of Hydrachnids. No similar case has been recorded. 

 The larva? seem to be very close to the larval forms of Neumamiia, a 

 •sub-genus of Atax. 



New Species of Koenenia.J — Augusta Rucker describes Kamenia 

 (Prokccnenia) wlieeleri from Texas. She places it beside Hansen's 

 Kccnenia (Prolmnenia) chilensis, accepting Borner's suggestion that the 

 sub-genus Prolccenenia should include those species possessing lung-sacs, 

 and that the sub-genus Eulmiienia should include those species not 

 possessing lung-sacs. A useful table is given of the habitats and dia- 

 gnostic characters of the known species of this interesting genus. 



e. Crustacea. 



Colour-Physiology of Higher Crustacea. § — F. Keeble and F. W. 

 Gamble have investigated the structure and function of the chromato- 

 phores of certain Schizopod and Decapod crustaceans with especial 

 reference to the effect of light on these organs and on these animals. 



Under the influence of light the secretory activity of certain organs 

 is modified ; an acid substance appears periodically in " liver " and 

 muscle ; the appearance and disappearance of this acid substance coin 

 cides broadly with nocturnal and diurnal colour-change. In the pro- 

 gressive movements and orientation of the whole animal called forth by 

 light, background is the most important factor, more important than 

 and sometimes reversing the influence of change in light-intensity. 



The response of the chromatophore pigments to light is twofold : 

 direct and indirect, the latter through the mediation of the eye. The 

 indirect response alone leads to an enduring redistribution of pigment. 



The ultimate effect of monochromatic light on pigment-movements 

 is the same as that of white light, but in both cases the background 



* SB. Ges. Naturf. Berlin, 1902, pp. 36-45 (3 figs.). 

 t Journ. Quekett Micr. Club. 1903, pp. 463-4 (4 figs.). 

 J Quart. Journ. Micr. Sci., slvii. (1903) pp. 215-31 (1 pi.). 

 § Proc. Roy. ISoc. London, lxxi. (1902) pp. 69-71. 



