400 SUMMARY OF CURRENT RESEARCHES RELATING TO 



logy of the malleus-incus articulation in mammals with the quadrato- 

 articular of other vertebrates. He holds that there are insuperable 

 morphological and physiological difficulties in accepting such homology, 

 and proves the homology of the lower jaw articulation in mammals 

 with that of the lower vertebrates. As an illustration of the evidence 

 adduced may be taken the relations of the trigeminus to the lower jaw 

 in Urodeles, which have no parallel in the malleus-incus articulation of 

 mammals. 



Early Development of Desmognathus fusca.* — H. H. "Wilder sup- 

 plements an earlier paper on this subject by an account of the develop- 

 ment during the first three days. The segmentation is at first almost 

 typically holoblastic, although in the later relation of embryo to yolk 

 it greatly resembles that of meroblastic embryos. 



b. Histolog-y. 



Ciliary Movement.f — E. A. Schafer refers to the theory of ciliary 

 movement which he stated in 1891. If cilia are hollow extensions of 

 the cell, occupied by hyaloplasm and invested by a delicate membrane, 

 thickened (or at any rate less extensible) either along one side or in a 

 spiral line, any tendency of the hyaloplasm of the cell to flow into or 

 out of such a hollow process — in other words, to increase or diminish 

 the tension within it- — must result in a bending movement if the line 

 of less extensibility were a straight one, or in a circular or corkscrew 

 movement if the line were a spiral one. And since the amoeboid 

 movements of cell protoplasm are in all probability due to local changes 

 in tension at the surface of the cell, this assumption regarding the 

 structure of cilia would at once bring their action into line with that 

 of other more general contractile manifestations of protoplasm. 



Prof. Schafer defends this theory against the interpretations recently 

 put forward by Dr. Piitter.J 



Structure of Mammalian Blood-vessels.§ — Baum and Thienel 

 point out the lack of definite knowledge which exists on the subject of 

 the microscopic structure of different types of blood-vessels. They have 

 made a comparative study of the arteries and veins in the region of the 

 axilla in horse, ass, ox, calf, sheep, pig and dog, the results of which are 

 detailed in the present paper. 



Nerve-endings of Human Skin.|| — A. S. Dogiel in a very full 

 paper confirms and extends the work of Ruffini on this subject. Some 

 new facts of interest are brought out. The nerve apparatus minus 

 capsule can be divided into two groups, that enclosed in connective 

 tissue and that in epithelium. To the apparatus of the first kind 

 belong the Ruffini corpuscles, the tree-shaped end branchings, the un- 

 encapsuled end ganglion, intra-papillary endings, ribbon-form bundles, 

 and nerve-fibre network (vaso-motor nerves in papillaj-Ruffini, and the 



* Anier. Naturalist, xxxviii. pp. 117-25. 



t Anat. Anzeig., xxiv. (1904) pp. 497-511. 



% Asher and Spiro. Ergebnisse der Physiologie, ii. Abth. 2. 



§ Arch. Mikr. Anat.. lxiii. (1903) pp. 10-31 (1 pi.). 



|| Zeitschr. wis*. Zool., lxxv. (1903) pp. 46-111 (10 pis.). 



