INVERTEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC. 929 



put out by Gegenbaur ; and in short he comes to the conclusion that 

 we have not as yet a sufficient body of facts to justify us in arriving 

 at any definite determination of what organs in the other Mollusca 

 are homologous to the renal organs of the Cephalopoda. 



Influence of Acids and Alkalies on Cephalopods.* — M. Yung 

 finds himself able to confirm, in these animals, most of the results 

 obtained by M. Eichet when operating on Crustacea. f 



The Cephalopoda are extremely sensitive to the action of mineral 

 acids ; with a slight dose the respiratory movements are accelerated ; 

 four specimens of Eledone moschata, resjiiring tweuty-four to twenty- 

 six times a minute, gave after five minutes in 2 litres of water con- 

 taining -5 cc. of sulphuric, nitric, liydrochloric, and oxalic acids, 

 respectively, fifty-six, forty-two, thirty-six, and thirty respirations a 

 minute. A double dose in the case of all but oxalic acid had a toxic 

 efiect, but sulphuric acid was the slowest in its results. 



The alkalies may be ranged in the following order of toxicity : — 

 ammonia, potash, sodium, calcium, baryta. The first is extremely 

 rapid ; with a dose of one per thousand, it kills almost at once ; the 

 respiratory movements are, at first, accelerated, and after having 

 reached a maximum which varies with the agent employed, they 

 gradually diminish. 



"Liver" of the Gastropoda. :{: — Dr. Barfurth is of opinion that this 

 organ is a hepato-paucreas ; his most important observations appear to 

 have been on Arion empiricorum, and in it he recognizes three kinds 

 of cells as comjiosing the gland in question. 



When fresh portions of the organ are suitably treated with osmic 

 acid, some of the cells rapidly become deejily tinged of a black colour ; 

 these are regarded as the preparers of the hepatic ferment ; their 

 contents are ordinarily large spheres, of a yellow or brown colour, iu 

 the fresh state ; the cells are generally elongate, and often spherical. 

 The second set of cells arc the true hepatic cells, with the nucleus 

 placed in their basal portion ; elongated in form, they are consider- 

 ably thickened near the lumen of the follicle ; their contents chiefly 

 consist of small, spherical, or irregularly shaped granules, which only 

 blacken after some hours' exposure to the influence of osmic acid ; 

 the secretion of these cells is soluble in alcohol or ether, contrary 

 to what hai)pons with the ferment-cells. The third form of cell is 

 filled with highly refractive colourless granules which consist in most 

 cases of carbonate of lime, allied with some organic substance ; but 

 their further characters have still to be investigated. 



Ditterenccs seem to obtain between the aquatic and terrestrial 

 Gastropods in their bcliaviour to chemieal reagents; the livers of the 

 former harden much ni(h-e slowly in absolute alcoliol and osmic acid, 

 and their ferment-cells do not blacken so quickly ; while the cal- 

 careous cells may be absent, scarce, or replaced by small crystals of 

 what is ai)parently oxalate of calcium. 



* 'Coiniiles ReiuluM,' xci. (1880) j). 43'J. 

 t See this Jntiriiftl, </»t/<', p. (J'2S. 

 X 'Zool. Anzei-.,' iii. (I8S0) \>. 191). 



