ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



441 



of Amphibians, or touch-spots of reptiles. The author does not find 

 that any of these theories can be accepted. Mammalian hairs are struc- 

 tures sui generis and peculiar to mammals. They have differentiated in 

 two directions— tactile and protective, but the tactile function is probably 

 the more primitive. 



A classification is proposed : — 



Hypothetical 

 primordial / 

 hair 



.A. Ordinary 

 I I hairs 



Hairs with--*, 

 out sinus 



B. Transition 

 hairs 



(A. Passive 

 tactile 

 hairs 

 B. Active 

 tactile 

 hairs 



la. Protective non-sensory hairs 



[b. Sensitive hairs, with one nervous 

 apparatus or with more than 

 one 



( a. Without an annular sinus 

 I b. With an annular sinus 



Mobile vibrissse 



c. 



General. 



Sense-organs of Invertebrates.* — Gustav Kafka has given a valuable 

 account of the sense-organs of Invertebrates, which implies much 

 microscopical detail. He deals with structures specialized as sensi- 

 tive to touch, movements of the body, sound, temperature, chemical 

 influences, light, colour, and so on. There are also two very interest- 

 ing chapters discussing " space-sense " (as in homing) and " time-sense " 

 {as in rhythmic responses to external periodicities). 



Influence of Salts. f — Erwin Hirsch, in conjunction with the late 

 W. Cronheim, has made numerous experiments, testing the influence of 

 various salts (in solution in the medium) on Daphnids, Ghironomus 

 larvae, eels, tadpoles, and other animals. He shows what the limits of 

 endurable concentration are, and compares the results with those reached 

 by others. He calls attention to some influences on development, on the 

 growth of appendages, and on pigmentation. The experimental results 

 are correlated with faunistic observations. 



Lateral Glands of Shrews.} — Sigurd Johnsen has made a study of 

 the gland which stretches along each side of the shrew's body. It 

 consists of strongly-developed sudorific glands, and of sebaceous glands 

 which are sometimes strongly developed, as in the male of Sorex araneus, 

 and sometimes not enlarged, as in the female of this species. In 

 Crocidura murina the sebaceous glands are ecpially developed in the two 

 sexes. The odoriferous secretion comes from the sudorific glands, but 

 it is possible that the sebaceous glands may contribute. The sebaceous 



* Einfiihrung in die Tierpsychologie. Erster Band. Die Sinne der Wirbellosen, 

 Leipzig : 1913; xii and 593 pp. (362 figs.). 



t Zool. Jahrb. Abth. Allg. Zool., xxxiv. (1914) pp. 559-682. 

 % Anat. Anzeig., xlvi. (1914) pp. 139-49 (9 figs.). 



