ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 449 



disappear, which in part explains the reduction in the volume of the 

 testis. Most of them seem inactive, but some have a differentiated 

 cytoplasm with a compact zone and a reticulate zone, a structure which 

 characterises active elements. 



Hybrid Newts.* — W. Wolterstorff discusses the significance of the 

 hybrids between Triton cristatus Laur. and Triton vulgaris L., and his 

 conclusion is that the hybrids, which Poll has also studied very carefully, 

 represent a primitive type of the sub-genus Triton sensu stricto. In Triton 

 alpestris, T. italicus, and T. marmoratus, we have to do with more or less 

 stable species, but T. vulgaris and T. cristatus are heterogeneous and 

 variable groups. 



Chondriosomes as Bearers of Inheritance.! — Fr. Meves calls 

 attention to the " Nebenkern " in the spermatids, which v. la Yalette 

 St. George showed to be composed of cytomicrosomes present in the 

 spermatocytes. These granules have had much study devoted to them 

 under the name of " rnitochrondria ;" they occur not only in the sperrna- 

 togenetic cells, but in differentiated somatic cells. Certain rodlets or 

 threads, composed of mitochondrial substance, having been studied by 

 Meves under the name of " chondriokonts," he now unites these with 

 mitochondria under the title " chondriosomes," and seeks by studies in 

 the early development of chick embryos to show that they may be justly 

 regarded as cytoplasmic bearers of heritable qualities. 



Notochord and Archenteron.J — D. D. Ussoff has studied the de- 

 velopment of the grass snake (Tropidonotus natrix), with particular 

 reference to the notochord. His three main conclusions are : — (1) the 

 notochord of Amniota, except at its anterior extremity, corresponds to a 

 modified coalesced archenteron in Amphioxus ; (2) the sclerotomes of 

 Amniota correspond to degenerated primitive segments in Amphioxus ; 

 and (3) the nervous system of Amniota increases the number of its cells 

 at the expense of the urochorda. 



Notochord Cartilage in Urodela.§— Fr. Krauss has studied this in 

 axolotl, newt, and salamander. The notochord-cartilage arises from 

 chorda-epithelium cells and from vacuolated chorda cells. The share 

 that these two kinds of cells take is described. Although the notochord 

 arises from endoderrnic epithelium, it should be referred to the chondroid 

 tissues, which include the vesicular supporting tissue in the tendon of 

 Achilles of the frog and, in various cartilages of hag and lamprey. The 

 notochord may be described as larval cartilage. 



Colours of Highland Cattle. || — James Wilson comes to the follow- 

 ing conclusions : — (1) There are four colours forming the basis of 

 present-day Highland colours, viz., black, blackish-brown or "donn," 

 red, and light dun. One other colour, white, and other " markings " 



* Zool. Anzeig., xxxiii. (1909) ppL 850-7. 



t Arch. Mikr. Anat., lxxii. (1908) pp. 816-67 (4 pis.). 



X Anat. Anzeig., xxxii. (1908) pp. 265-70 (5 figs.). 



§ Arch. Mikr. Anat., lxxiii. (1908) pp. 69-116 (3 pis.). 



|| Sci. Proc. R. Dublin Soc, xii. (1909) pp. 66-76 (1 pi.). 



Aug. 18th, 1909 2 H 



