ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 35 



Influence of Soil on Fauna.* — J. A. CI. Koux, in his geological 

 study of the Lyonuese mountai ns, applies his results to an interpretation 

 of the peculiarities of the region, not only climatic, economic, and 

 hygienic, but also as regards the fauna and flora. He comes to the con- 

 clusion that the absence of calcareous salts has an undeniable influence 

 on the animal life. In general terms, the fauna of a siliceous region is 

 less vigorous, less rich, less varied in species, less abundant in indi- 

 viduals, than a calcareous region. This is particularly true as regards 

 molluscs, certain kinds of insects, crustaceans, and worms, but it also 

 affects Vertebrate forms. 



Perhaps the best illustration is furnished by the terrestrial snails, 

 which are poorer in numbers and species, smaller in size, and have more 

 delicate shells. On the other hand, to pass to the other end of the 

 scale, the Heliozoa, like Acanthocystis, are extremely abundant, and are 

 remarkable for the fine proportions of their siliceous skeletons. The 

 essay is a most interesting one in its detailed attempt to correlate geo- 

 logical and biological facts. 



Habitat of Whales. f — Dr. Ernst Vauhoffen contests the usual state- 

 ment that whales and the Cetacea generally are inhabitants of the high 

 seas. The various plankton expeditions have recorded with much exact- 

 ness the numbers of whales seen, and their observations go to show 

 that whales and dolphins are in reality shore-haunting animals. This 

 is confirmed by the plankton records, which show that surface forms are 

 most abundant near the shore, where their numbers are continually re- 

 inforced by the larvae of the littoral animals. Where whales are fre- 

 quently found in the high seas, observation shows that the area is one 

 to which currents carry the abundant plankton of the shore waters. 



Tunicata. * 



Embryology of Salpa.J — Herr Alexis Korotneff has been enabled to 

 supplement his observations on S. fusiformis by an investigation of the 

 early stages of S. maxima-africana. Some of his sections show the forma- 

 tion of a polar body, which is of much interest, because it is as large as 

 the egg-cell itself; it may be that this is the primitive condition (cf. 

 Boveri). In regard to the segmentation, the following special points 

 were noted. From a very early stage the blastomeres are differentiated 

 into a few large and numerous small cells. The former display yolk- 

 spherules in the later stages of segmentation, but the author believes 

 that these arise from a differentiation of the protoplasm of the cells, and 

 not from follicle-cells taken up by these blastomeres. Among the small 

 blastomeres certain cells are early differentiated as germ-cells. Later 

 the distinction between macromeres and micromeres is obliterated. As 

 to the origin of the atrial chamber, the observations on the present 

 species confirm the author's previous statements that this originates as a 

 split in a mass of follicle-cells, and spreads by the separation of the 

 elements and not by a process of invagination. The basal plate is an 

 entirely provisional structure, formed of follicle-cells, and quite with- 

 out the importance assigned to it by Heider. 



* Aim. Soc. Linn. Lyon, xlv. (1899) pp. 105-56. 



t Zool. Anzeig., xxii. (1899) pp. 396-101 



J Zeitschr f. wies. Zool., lxvi. (1899) pp. 625-6 (3 pis.). 



D 2 



