INVERTEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC. 413 



digestion period, but in the Coelenterata no such secretion is to be dis- 

 covered and it is to be concluded that tbe nutritive processes of the 

 Coelenterata are all resorptive. 



The author gives further an account of his investigations into a 

 number of Sponges, Echinodermata and Mollusca. 



Effects of Poisons on Invertehrata.* — Dr. Krukenberg also gives 

 an account of his " comparative toxicological " studies on various Inver- 

 tehrata ; the subjects were Hirudo officinalis, Astacus fluviatilis, Helix 

 pomatia, Spurilla neapolitana, Synapta digitata, Sagartia troglodytes, and 

 Turris digitalis. The chief drugs used were chloroform, atroj)in, cam- 

 phor, strychnin, morphin, catfein, compounds of sodium and potassium, 

 curare, and veratriu. There is also a short note on the influence of 

 curare on the larva of Sphinx euphorhice. 



Distribution of Chlorophyll in Invertebrata.f — In a postscript to 

 his paper on the Chlorophyll of the Green Planaria,| Mr. Geddes states 

 that he has more recently examined Bonellia viridis and Idotea viridis 

 at Naples. With regard to the former he supports the views of M. 

 Lacaze-Duthiers and of Mr. Sorby, as against the chlorophylloid 

 character of the green colouring matter of Bonellia. A Bonellia in full 

 activity was placed in a glass tube in the light ; after half an hour 

 the water took on a pale green tint, and half an hour afterwards the 

 animal appeared to be dead. Not one bubble of gas was formed 

 during the investigation. Very similar results were obtained with 

 Idotea. These investigations are exceedingly interesting when 

 compared with the very striking differences exhibited by the green 

 Planarians. 



Pelagic Fauna of the Lakes of Tessin and Italy. § — The obser- 

 vations in which Professor Pavesi, of Pavia, has lately been engaged 

 on the pelagic fauna of the lakes of Tessin and of Italy have yielded 

 interesting results. Twenty-one lakes were examined, mostly in 

 Italy. 



The tables show that Leptodora is found almost everywhere. 

 Daphnclla hrachyura, Daphnia hyalina, D. galeata, Bosmina longirostris, 

 Gyclops minutus, &c., are very common ; on the other liand, Sida crys- 

 lallina, Daphnia qnadrangida, Bosmina longispina, and Bythotrephes arc 

 rare; lastly, Daphnia magna and D. crystallina are localized in the 

 single Lake of Idro. It is a curious fact tliut of two lakes, near each 

 other and of the same geological origin, and frc(piented by the same 

 acpiatic birds, one may present hardly any pelagic forms, wliile the 

 other may have many. Such are the small Lake of Candia and tho 

 Lake of Viveronc (tliey also show a difference of the opposite kind in 

 algologicul flora), 'i'he latter lake, indeed, is triple that of the former, 

 and about five times as deep. Still, great depth is not necessary to 

 the existence of pelagic animals, though it is more favourable to their 



• Loc. cit., p. .O?. 



t ' Arrli. Zodl. cxpiT. ct f^vw.' (I.acnzc-Dutliiors), viii. (1S80) p. 51. 

 X Sic tliirt .JiMiniiil, ii. (lS7it) j). KJl. 



§ 'Arcli. t?ei. I'liys. ct Nut.,' iii. (ISSO) p ir>l ; son 'Nature,' xxi. (lS,s(i) 

 n. 525. 



