ZOOLOGY A.ND BOTANY, MICROSCOPY, ETC. 287 



Development of the Middle Ear in Emys europsea.* — Noack gives 

 an account of the conditions observed in several embryonic stages of 

 the middle ear in this tortoise. In particular he has investigated the 

 question of the origin of the columella auris, and has failed to establish 

 any connection of the columella blastema with that of the hyoid arch. 

 He consequently denies to it any hyal origin. 



Nasal Skeleton of Amblystoma punctatum.f — R. J. Terry gives 

 an account of the structure and development of the nasal skeleton. We 

 can only quote the last paragraph of the paper : " In Amblystoma the 

 cartilaginous nasal capsule does not arise independently of the brain- 

 case. It is from the beginning a part of the ethmoidal skeleton which 

 is built in connection with the trabecule, ethmoidal columns and 

 antorbital processes. In the development of the cartilaginous ethmoidal 

 skeleton, there are formed, pari passu, a capsular covering for the 

 epithelium of the nasal sac and protecting walls for the olfactory bulb." 



Phagocytosis of Metamorphosis. | — L. Mercier has studied this in 

 Anura and in the Muscidaj. AYe quote only his conclusions on the role 

 of the leucocytes in the degeneration of muscle fibres. The active 

 participation of the leucocytes in such degeneration is established. As 

 long as histolysis of the fibres is evident they do not appear. The 

 sarcoplasm becomes vacuolar, the nuclei show chromatolytic degenera- 

 tion, and the fibres break at their extremities. Until this stage the 

 sarcolemma remains intact. The phagocytary process consists of : 

 (fl) the phase of isolation : the leucocytes form a real sheath round the 

 degenerating fibres. (J) The penetration of the leucocytes. This has 

 as an immediate result the agglutination of the fibrils which form a 

 homogeneous layer. Out of this the leucocytes cut pieces, suggestive 

 of punched holes, (c) Fragmentation of the fibres into sarcolytes, which 

 are enveloped and digested by the leucocytes. Other points discussed in 

 this exhaustive memoir are the development of the leucocytes, the de- 

 generation of the caudal epidermis in the Anura {Rana temporaria), 

 experimental phagocytosis, etc. 



Amitosis as a Factor in Normal and Regulatory Growth.§ — 

 C. M. Child communicates facts suggesting that amitosis is of frequent 

 occurrence in the normal development of many forms. Examples are 

 given from Tubularia mesemhryanthemvm, Corymorpha palma, Planarta 

 maculata, various Cestodes, Annelids, and Chordates. It is evidently 

 not the rare and exceptional process which it has been supposed to be, 

 although it is possible that the term may be found to include a variety 

 of nuclear phenomena depending on quantitatively and perhaps qualita- 

 tively different conditions and leading to different results. The most 

 characteristic feature in all cases of amitosis described is the apparently 

 non-cyclical or orthodromic character of the processes involved, as far as 

 the nuclear contents are concerned. These processes appear to consist 



* Arch. Mikr. Anat., Ixix. (1907) pp. 457-90 (1 pi. and 6 figs.). 

 t Trans. Acad. Sci. St. Louis, xvi. (1906) pp. 96-124 (4 pis.), 

 t Arch. Zool. Exp6r. et G^n., s6r. 4, v. (1906) pp. 1-151 (4 pis.). 

 § Anat. Anzeig., xxx. (1907) pp. 271-97 (12 figs.). 



