ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 187 



ment, for it is not a hardy fish. It will not survive more than three 

 or four hours out of water, and then ouly under the most favourable 

 conditions. " Physiologically at least, therefore, Polyplerus has not 

 evolved very far toward a land-living or even an air-breathing type, 

 although morphologically, i.e. especially in its organs of respiration 

 and circulation, it certainly presents the essential characters of the 

 lower amphibia. . . . On the other hand, in the possession of spiracles 

 and in primitive skeletal characters, it strongly resembles the oldest 

 fishes (Elasmobianchii). Several writers have recently contributed very 

 convincing evidence that crossopterygians were lineal ancestors of the 

 higher vertebrates ; but, judging from the conditions in Polypterus, 

 they were also sufficiently remote in the phylum of vertebrates to have 

 given rise to both dipnoans and amphibians." 



Effect of Starvation on Fishes.* — Prof. E. Yung and Dr. 0. Fuhr- 

 mann have investigated this subject by keeping fish under precisely 

 similar conditions, save that while one set were furnished with abundant 

 food, the other set were unfed. Thus two pike (Esox Lucius) of the 

 same size were kept under observation for eight months under these 

 conditions. At the end of this time both were killed, and the gut in 

 each case subjected to careful examination. In A (the fed specimen) 

 the gut was invested by fat, totally absent in B (the starved specimen). 

 Further, in B the gut was relatively shorter, the folds of the mucous 

 membrane of stomach and oesophagus had become indistinct, and the 

 whole tube had become greatly reduced. The reduction of its wall did 

 not affect all the elements equally, but was greatest in the epithelium, 

 whose elements were much reduced in size, while the other constituents 

 were affected in the following order : — glandular elements, connective- 

 tissue layer of mucosa and sub-mucosa, finally, least of all, the circular 

 and longitudinal muscular layers. The liver in B was much reduced 

 in size, and its constituent cells were 8-10 times narrower than those 

 of A, but this reduction chiefly affected the cytoplasm, the nucleus 

 being reduced only by about one-half. 



Experiments on the Electric Organ of Torpedo.f — Herr S. Garten 

 has observed the effects of cutting the nerve which supplies the electric 

 organ, and of poisoning with curare and veratrin. Without goin<* into 

 details, we may note the general conclusion that all the phenomena are 

 reconcilable on the view that the terminal nervous expansion or a struc- 

 ture intimately bound up therewith is the seat of electromotor activity. 

 This is specially supported by the fact that after the nerve is cut the 

 organ becomes rapidly unexcitable either directly or indirectly. The 

 muscular origin of the electromotor activity is rendered improbable. 



Function of Caecum in Lancelet.J— Herr Guido Schneider has made 

 some experiments on living lancelets which go to show that the csecum 

 or liver has to do with excretion. Ammoniacal carmine, whether intro- 

 duced through the alimentary canal or otherwise injected, is afterwards 

 found in the liver-cells. t These elements contain excretory vacuoles in the 

 parts towards the lumen of the csecum, and very minute pigment-granules 



|g * Arch. Sci. Pkys. et Nat., viii. (1899) pp. 4S3-5. 

 t Abh. K. Sachsisch. Ges. Wiss., xxv. (1899) pp. 253-366 (4 pis ) ' 

 X Anat. Anzeig., xvi. (1899) pp. 601-5 (2 figs.). 



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