284 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Dangeard's study of Flagellates shows (1) that these laws have only 

 a secondary importance, and (2) that they express the result of modifica- 

 tions introduced into the cellular organism in the course of evolution. 

 The division in Flagellates is often quite contrary to the laws of Hertwig 

 and Pfliiger. 



Dangeard re-states the laws of division : — 



(1) The nuclear axis is disposed at right angles to the cellular axis 

 or to the cellular plane if there is one. 



(2) The plane of division passes through the axis or the cellular 

 plane, and these are determined by the general morphology of the cell 

 and the position of its permanent elements. 



Taking the cases of Euglenopsis vorax and Trachelomonas volvocina, 

 Dangeard shows that the primary laws are modified by the appearance 

 of a membrane or non-extensible membrane. The laws of Hertwig and 

 Pfliiger relate to this secondarily induced modification. 



Size of Nerve-Fibres in Fishes.* — C. J. Herrick directs attention 

 to Miss Dunn's observations upon the relation between diameter and 

 distribution of nerve-fibres in the frog. They recall some facts which 

 he noted in regard to fishes. He concludes that each functional system 

 of peripheral nerves has tolerably definite fibre-characteristics, the basis 

 for which is as yet unknown ; that these characteristics are by no means 

 invariable, but that the fibres of a given system may show considerable 

 differences in calibre and medullation in a single animal ; and that some 

 of these differences, at least, may be correlated with the degree of 

 functional development of the peripheral end-organ. In general, highly 

 developed muscle-fibres, sense organs, &c. receive larger nerve-fibres, 

 than similar organs in a state of structural and functional degradation. 



Nerve-Endings in White Muscle.f — A. Motta Coco and S. Distefano 

 have studied the nerve-terminations in the white muscle of the rabbit, 

 and have shown that these are distinctly different in structure from 

 those on the red muscles. 



Integumentary Organs of Cervidge4— E. H. Zietzschmann has 

 studied the minute structure of various organs beneath the skin of 

 Cervidse. He begins with the hair-tufts on the tarsal or metatarsal 

 regions, or on both. These tufts differ in colour from the adjacent 

 parts, the hairs are usually longer and coarser, and more closely packed 

 (except in the roedeer). In many cases there are associated hairless 

 patches. The skin of the hair- tufts is specially thick and shows a 

 crowding together of tubular and acinous glands. 



Secondly, the author discusses the " Brunftfaltm " in Cervus elaphus 

 — a folding of the skin in the position of the antlers in females and 

 young males. All three layers of the skin are folded ; there is no 

 increase in the tubular (sweat) glands, and there is no very marked 

 increase in the acinous glands ; in young males, indeed, the latter are 

 absent. Similar structures in other forms are described. 



The head-folds of Cervuliis muntjac are then dealt with ; they show 



* Journ. Comp. Neurol., xii. (1902) pp. 329-34. 

 + Anat. Anzeig., xxii. (1903) pp. 457-66 (3 figs.). 

 % Zeitsehr. wiss. Zool., lxxiv. (1903) pp. 1-63 (3 pis.). 



