ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 173 



■deals with sparrows, swallows, vireos, warblers, wrens, titmice, and 

 thrushes. 



Jaw-Muscles of Snakes in Relation to the Poison-Gland.* — 

 Nils Rosen gives an account of M. masseter and M. temporalis in various 

 snakes. He finds that M. masseter (M. par.-quadr.-mandib.), and espe- 

 cially the first portion of it, has an important role in compressing the 

 poison-gland. He does not deny a minor role to other muscles, and to 

 the tension of the ligammtum sygomaticum. 



Locomotion of Snakes.f — P. Buffa has made a detailed study of 

 the musculature of the skin, and gives the particulars in each of twenty- 

 three species. As a result, he concludes that crawling in serpents is the 

 result of the very complex relations of two different categories of move- 

 ment. These are movements of the scales, the whole integument and 

 the ribs, which last are controlled by the special connections existing 

 between the scales and integument. The second set of movements are 

 those instituted by the muscles uniting the scales themselves, and uniting 

 scales and ribs. The ribs act as a fulcrum to the body, in which func- 

 tion the undulatory movements of the body as a whole undoubtedly 

 take part. 



Effect of Heat on Colour-Changes of Anolis Carolinensis.f — 

 (j. H. Parker and S. A. Starratt find that the temperature is a factor 

 in the colour-change of this lizard. At 10° C. the animal becomes brown, 

 and remains so irrespective of illumination (115 candle-metres). At 

 this temperature heat is the controlling factor. At 40° and 45° C., the 

 lizard becomes green or greenish-grey, and remains so irrespective of 

 illumination (115 candle-metres). Here again heat is the controlling 

 factor. At intermediate temperatures, 20°-35°, light (115 candle-metres) 

 and dark are controlling factors, but the effect of heat is still evident 

 over this range in that it may influence the rate of the colour-changes. 



Influence of Food on Length of Intestine in Tadpoles. § — Emile 

 Yung has experimented with the larva? of Ra/ia esculenta, by giving them 

 different kinds of food. Whatever the diet be, the intestine elongates 

 rapidly until the hind limbs appear, then it diminishes until the develop- 

 ment of the hind limbs is complete, after which it elongates slightly. 

 From the time the fore limbs show themselves, the intestine shortens 

 persistently. 



The vegetarian larvae always have a longer intestine than the carni- 

 vorous forms. The difference is most marked during the period before 

 the appearance of the hind limbs. The fact that the shortening of the 

 intestine, common to all larvae, but most marked in the vegetarian forms, 

 coincides with the periods of metamorphosis during which the larvae 

 eat little or nothing, lends support to the view that the length of the 

 intestine is a function of the quantity of food which it contains. 



* Zool. Anzeig., xxviii. (1904) pp. 1-7 (6 figs.). 



t Atti Accud. Sci. Veneto-Trentino-Istriana, Anno I. (1905) pp. 145-237 (4 pis.). 



X Proc. Amer. Acad., xl. (1904) pp. 457-66. 



§ Comptes Rendus cxxxix. (1904) pp. 749-51. 



