218 SUMMARY OF CUERENT RESEARCHES RELATING TO 



presenting many analogies to the gland-cells of mucous glands. The 

 smallest kinds are found in the cystic epithelium of Triton cristatus ; 

 aggregates, such as are seen in Bana, and especially in Bufo, do not 

 seem to be there present. In Bufo vulgaris and Bomhinator igneus 

 they are very abundant ; in Hyla arborea they are also numerous, 

 but more scattered than in toads. 



Nerve-terminations in the Cutaneous Epithelium of the Tad- 

 pole.* — Mr. A. B. Macallum summarizes the results of his research 

 thus: — Certain fibres of the nerve-network, situated below the 

 corium, and known as the fundamental plexus, give origin to fibrils 

 which enter the epithelium and terminate in comparatively large beadlike 

 bodies between the cells. From a network of fine fibrils below the epi- 

 thelium and forming meshes, each narrower than the surface covered by 

 an epithelial cell, arise other excessively fine fibrils, which end either 

 within or between the cells, or after branching, in both fashions. One, 

 commonly two, often three or more, nerve-fibrils terminate in the 

 interior of each epithelial cell, near its nucleus. The so-called 

 figures of Eberth, which are found during larval life only, which are 

 easily isolated from the cells containing them, and which were 

 regarded by their discoverer as intracellular nerve-terminations, 

 appear to Mr. Macullum to be sheaths for such terminations. The 

 epithelium was hardened with Erlicki's fluid, or solutions of chromic 

 acid of different strengths; for staining, nigrosin and safranin, as 

 well as, of course, gold chloride were used. 



Phenomena of Muscular Contraction in Primitive Striated 

 Fibres.f — M. F. Laulanie has studied the hyoid muscles of the frog 

 with the aid of the myoscope, and finds that the contraction of the 

 primitive fibres of the hyoid muscles of the frog produce no change 

 either in the character of the striation or in the relative situation 

 of the parts of the contractile segment. The author thinks that this 

 result justifies us in rejecting all theories as yet proposed to explain 

 the muscular contraction, all of which imply a change either in the 

 distribution of the parts, or in the situation. It is further found that 

 the disc and the clear bands flatten and enlarge without altering in 

 volume, and it is concluded that the contraction of the fibrils of the 

 primitive bundle is the summation of the changes of form (flattening) 

 undergone by the thick discs and the clear bands. The heterogeneity 

 of the fibril can as yet be only explained by the theory of M. Eanvier 

 that the fragmentation of the contractile substance offers a very large 

 surface for chemical changes, and so insures their rapidity. 



y. General. J 



Organs of Flight.§ — M. P. C. Amans sums up an extensive 

 survey of the organs of flight of the animal kingdom by distinguish- 

 ing two principal types of the machine — ^the insect and the vertebrate. 



* Quart. Joum. Micr. Sci., xxvi. (1885) pp. 53-70 (1 pi.), 

 t Comptes Eendus, ci. (1885) pp. 705-7. 



X Tills section is limited to papers which, while relating to Vertebrata, 

 have a direct or indirect bearing on Invcrtcbrata also. 

 § Auu. Sci. Nat.— Zool., xix. (1885) pp. 9-222 (8 pis.). 



