558 SUMMARY OF CURRENT RESEARCHES RELATING TO 



and examined the result in twenty-three weeks. There was a new and 



independent piece of bone intercalated, 2 mm. in length, which the 



experimenter regards as supernumerary phalanx. It appeared separately 

 in the proliferation of periosteum at the wound. 



Mitochondria of Hepatic Cells.* — Andre Mayer, Francis Rathery, 

 and Georges Schaeffer find that definite granulations or mitochondria 

 occur normally in the cells of the liver, and apart from all reagents. 

 They form a constituent part of the cells, and do not show any appre- 

 ciable change in number or in aspect with different modes of treatment. 

 They do not behave as reserve substances. 



Clasmatocytes.f — F. Pardi has made a study of Ranvier's clasmato- 

 cytes in Amphibians and in Mammals. In the former they are ramified 

 " Mastzellen, 1 ' often showing fragmentation. In the latter they are quite 

 different from " Mastzellen," and are in genetic relation with minute 

 cells like lymphocytes which migrate from the connective-tissue. 



Visible Centrosomes in Living Cells.} — Fr. Heiderich has succeeded 

 in seeing the centrosome in living cells from the mucous membrane of 

 the stomach of the frog, the cat, the dog, and the horse, and in the 

 posterior corneal epithelium of the cat. The position of the centrosome 

 has been previously seen in living pigment cells of fishes (by Solger), in 

 living leucocytes (by Heidenhain). The centrosome itself has been 

 seen in living summer ova of Jlesostoma ehrenbergi (by Bresslau) and in 

 living blastomeres of Ascaris (by Boveri). 



c General. 



Mimicry.§ — Geza Entz, sen., publishes the third and concluding 

 portion of his study of animal coloration. The present paper deals 

 with mimicry, and its general conclusions may be summed up as follows. 

 Many cases of resemblance occur not only among animals of allied races, 

 but also among those of quite different descent. Many animals resemble 

 portions of the bodies of other animals, other plants or parts of plants, 

 while many plants resemble animals or parts of animals. Sometimes 

 the resemblance is so slight that it could only deceive the most casual 

 observer for a moment, in others it extends to the most minute details, 

 and goes far beyond the requirements of the mimicry-theory. In many 

 cases, indeed in the great majority, the mimicry is of no use either to 

 the mimetic species or its model. Defenceless animals imitate others 

 equally defenceless, aquatic animals imitate terrestrial forms, recent 

 animals those that have long been extinct, and so on. In regard to 

 such cases, the " mutual assurance theory," ingenious as it is, can hardly 

 satisfy the naturalist. Even in cases of " true mimicry," in which some 

 advantage to the mimetic species can be demonstrated," the utility of the 

 mimetic habit has been greatly exaggerated. The whole theory rests 

 upon the anthropomorphic conception that animals perceive and pursue 

 their prey in exactly the same way as human beings do. If mimetic 



* C.R. Soc. Biol. Paris, lxviii. (1910) pp. 4:27-9. 



f Atti Soc. Toscana Sci. Nat. Pisa, xxv. (1909) pp. 59-S6 (2 pis.). 



X Auat. Auzeig., xxxvi. (1910) pp. 614-18(1 pi.). 



§ Math. Naturw. Ber. Ungarn , xxv., (1909) pp. 1-94. 



