ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 289 



which this fish cau change its colour in adaptation to that of its 

 surroundings. There is a hghtness of yellow and a darkness of green 

 which the fish cannot exceed, and two hours suffice to enable it to 

 change from one extreme to the other. 



Taillessness in Rat.* — Sara B. Conrow has made a careful examina- 

 tion of three tailless rats, and has found that all of them lacked all of 

 the caudal vertebrge. Besides this, the first lacked one sacral vertebra ; 

 the second, two sacral vertebrae ; the third, four sacral vertebras and a 

 lumbar or perhaps two lumbars. In each case the vertebral column 

 terminated in the pelvic region far anterior to the posterior end of the 

 body, showing that the tailless condition was due not to accident after 

 birth, but to a congenital deformity of the vertebral column. 



Secretion in the Thyroid Gland. f — R. R. Bensley discusses the 

 various views, and concludes that the colloid material isa true secretion-: 

 antecedent, representing material formed in the base of the cell for the 

 purpose of direct transport into the vascular channels. Under normal 

 conditions of functioning the secretion is excreted from the cell directly 

 without passing by the indirect route through the follicular cavity. 

 But in other conditions there is an indirect mode, which consists in the 

 condensation of the secretion into the form of droplets having a high 

 content of solids, and the extrusion of these droplets into the follicular 

 cavity. 



Variations in G-arter-snake.l — Joseph C. Thompson gives an 

 account of the variations in the scales of specimens of Thamnophis 

 ordinoides, taken within n radius of 3 kilometres near the Golden Gate. 

 The species presents a remarkably large series of variations. The food 

 consists entirely of large slugs of the genus Agriolimax. 



INVERTEBRATA. 



Mollusca. 

 o. Cephalopoda. 



New Species of Argonauta.§ — G. S. Coen discusses the shells of 

 the Adriatic representatives of this interesting genus. He describes 

 A. monterosatoi sp. n., showing how it differs as regards shell from 

 A. argo and A. rygnus. 



5. Iiamellibrancliiata. 



Living Varieties of Cockle.j|— G. S. Coen discusses and figures 

 numerous living varieties of Gardium tuberculatum, or, as it is called, 

 Eucardium {Rudicardmni) tuberculatum. 



* Anat. Kecord, ix. (1915) pp. 777-84 (3 figs.). 



t Amer. Journ. Anat., xix. (1916) pp. 37-54 (1 pi.). 



X Proc. U.S. Nat. Museum, xlvii. (1915) pp. 351-60. 



§ Ann. Mus. Storia Nat. Geneva, xlvi. (1915) pp. 271-5 (1 pL). 



II Ann. Tilus. Storia Nat. Geneva, xlvi. (1915) pp. 299-304 (5 pis.). 



