744 SUMMARY OF CURRENT RESEARCHES RELATING TO 



spermatogonia. The spermatocytes correspond to ova ; the two divi- 

 sions which they exhibit represent the extrusions of polar bodies. In 

 both cases there is a reduction of the chromatin to one-fourth of the 

 original quantity, and the second division follows on the heels of the 

 first without an intervening resting stage. The author works out in 

 detail the parallelism between ovum and spermatocyte, and points out 

 that Weismann's distinction between the fii'st and second polar body, 

 should logically hold true also for the products of spermatocyte division. 

 These, however, are all equal and similar. In regard to the formation 

 of j)olar bodies, Platner notes that the ovum at the time of extruding the 

 first polar body contains only the naked centrosoma without any trace 

 of archoplasma. The latter aj)pears for the fii'st time on the origin of 

 the polar radiations round each centrosoma, and its previous absence 

 may perhajDS explain the inequality uf the division in the formation of 

 the jiolar bodies. In addition to the above-mentioned parallelism 

 between ovurn and spermatocyte, one of the most interesting facts con- 

 firmed by Platner's research is the importance of the centrosoma as a 

 cell-centre. 



Habits of certain Borneo Butterflies.* — Mr. S. B. J. Skevtchly 

 finds that in the forest depths buttei-flies are rare, most delighting either 

 in the sunshine, or flying where it is close at hand. It is not the case 

 that a number of butterflies are to be found high overhead on the forest- 

 tops ; nowhere, even where trees were in flower, were butterflies seen in 

 numbe", although other kinds of insects were not rare. The majority of 

 butterflies still fly near the gi'ound, and possibly all did so originally. 

 In Borneo neither does heavy weather debar them, nor do flowering 

 creepers attract them to fly high; "this seems to point, as many facts 

 do, to butterflies being still as much terrestrial as aerial creatures." 



In dealing with the habits of particular species, the arithor notes 

 that, in some cases, tlie females woo the males, and in some cases are 

 both wooer and chooser. As there seems to be so little relation between 

 the habits, beauty, and numbers of the sexes, and the sex of the wooer, 

 it is difficult to see why we should introduce the complex machinery of 

 sexual selection to perform what the ordinary laws of evolution seem 

 equally capable of carrying out. Leptocircus curius has the habit of 

 pushing its proboscis into wet sand, taking long steady drinks, and 

 pu nping the water out astern in rhythmic squirts. 



Odoriferous Glands of Blaps mortisaga-f — Prof. G. Gilson has 

 exam'ned the structure of the odoriferous glands of this Coleopteron, 

 and of some other species. In Blaps the odoriferous apparatus is very 

 well developed, and consists of cutaneous unicellular glands; these cells 

 are so arranged as to form lobes which resemble glandular tubes, from 

 which they essentially difier in that each cell has a special excretory tube. 

 In each cell four parts can be distinguished ; there is a radiated vesicle, a 

 central ampulla, a delicate excretory tube, and a tube-sheath. The 

 solid portions of these parts are intimately connected with the reticulum 

 of the cytoplasm. The internal rays of the vesicle, and of the sheath 

 are orderly, and strengthened by radial trabeculsB of the cytoplasm. 

 The membrane of the vesicle, and those of the sheath, tube, and ampulla, 

 are formations which are analogous to cellular and nucleated membranes, 



* Ann. and Mag. Nat. Hist., iv. (1889) pp. 209-18. 

 t La Cellule, v. (1889) pp. 3-21 (1 pi.). 



