30 SUMMARY OP OUREENT RESEARCHES RELATING TO 



Markings of Mammals.* — Prof. G. H. T. Eimer continues his 

 interesting studies on the markings of mammals. In previous papers 

 he has dealt with cats, dogs, civets, hysenas, &c. ; the present (6th) 

 paper, which is well illustrated, discusses bears, martens and allied 

 forms. It is well known that Prof. Eimer regards these markings as 

 important indices of the history and relations of the animals. They 

 seem in reality like the most external finger-posts of the constitutional 

 progress. The individual in this, as in other particulars, recapitulates 

 the history of the race. The males usually gain the new qualities first. 

 New features appear on definite parts of the body, and spread in a fixed 

 and definite path. They may disappear as in an orderly phantasmagoria 

 and a new procession begins. The new features generally appear in the 

 hind quarters ; on the fore-parts the old features linger longest. This 

 Eimer calls the postero-anterior order of succession. Along with this 

 an undulatory series from below upwards is also sometimes demonstrable. 

 The above observations apply in part to birds, reptiles, butterflies, &c., 

 as well as to mammals. In the latter, a longitudinal striping is the 

 original state, from a modification of this spots arise, then cross stripes, 

 and often uniformity of colouring. 



Colour of Birds' Eggs."]" — Mr. A. H. S. Lucas discusses how the 

 colouring of birds' eggs has been acquired, and how it comes to be 

 protective or otherwise beneficial. He considers that the efiect of the 

 surroundings, during the time of the formation of the shell, upon the 

 mental or nervous constitution of the bird, is a very important factor in 

 determining the colouring of the eggs. Numerous illustrations of this 

 are noted. Any variations of value in rendering the eggs less con- 

 spicuous are seized on by natural selection and transmitted by heredity. 

 Individuals at the present day are influenced in part by the surroundings, 

 but mainly restricted by the tribal habits of generations. Hence there 

 is sufficient adherence to type to make an experienced collector tolerably 

 sure of the species of a bird to which a particular egg belongs, while, at 

 the same time, there are considerable differences even between eggs of 

 the same clutch. 



Development of Germinal Layers and Notochord in Rana fusca.J 

 ■ — Dr. O. Schultze has made an examination of the early developmental 

 stages of Bana fusca. He finds that there is no bilaminate gastrula- 

 stage, the rudiments of the middle and inner germinal layers arising 

 cotemporaneously by invagination. The middle layer, as well as the 

 dorsal wall of the archenteron, arises from the ectoblast, and at the 

 dorsal lip of the blastopore all the three layers pass into one another ; in 

 the lateral and ventral parts of the blastopore the covering layer of the 

 outer germinal layer is distinctly continuous with the endoblast, while 

 the basement layer of the ectoblast passes uninterruptedly into the meso- 

 blast. About the end of the invagination-period the fused portions of 

 the outer and median layer which are seen at the dorsal lip grow in the 

 direction of the dorsal median line, and so form the primitive stripes of 

 the embryo of the frog. Anteriorly to this the earliest rudiment of the 

 notochord is formed as a thickening of the mesoblast. The whole length 



* Humboldt, vii. (1888) pp. 1-9 (11 figs, and 1 pi.). 

 t Trans. Eoy. Soc. Victoria, xxiv. (1888) pp. 52-60. 

 X Zeitschr. f. Wiss. Zool., xlvii. (1888) pp. 325-52 (2 pis). 



