ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 291 



at the South Orkneys, where the summer population on Laurie Island 

 alone was estimated at not less than one million birds. Among the im- 

 portant results we may note the finding of the eggs of the familiar Cape 

 petrel (hitherto unknown to science) and of the chicks and young of the 

 ringed penguin (Pygoscelis antarcticci) and the snowy petrel (Pagodroma 

 nivea), the remarkable extension of the known range of the Macaroni 

 penguin (JJatarrhactes chrysolophus), and of Fregetta melanog aster, which 

 was undoubtedly breeding. There are some beautiful plates by H. 

 Goodchild. 



Skeleton of Tail in Birds.* — E. D. van Oort has made a study 

 of the osteology of the tail in representatives of the main orders of birds, 

 and has studied the development in the partridge, the black-headed gull, 

 the moor-hen, and other forms. He discusses the taxonomic value of 

 his results. 



Semicircular Canals in Birds.f — J. Laudenbach has investigated the 

 semicircular canals in a representative series of birds. They are least 

 developed in swimming birds, best developed in the swallow. Experi- 

 mental as well as anatomical results lead the author to conclude that the 

 degree of development of the semicircular canals is correlated with the 

 precision and nicety of equilibration in flight. 



Habits of Necturus.J — Albert C. Eycleshymer has studied Necturus 

 maculosus Rafinesque. The adults vary from 12-18 in. in length ; the 

 coloration is very variable, and probably can be changed by the in- 

 dividual animal ; the environment to which the animal is best adapted 

 is not known ; a casting of the epidermis was observed in winter ; the 

 time of egg-laying varies greatly with the temperature ; the eggs were 

 first deposited in those localities where the water is shallow, and exposed 

 for the greater part of the day to the sun ; the period of egg-laying 

 usually covers two or three weeks ; during egg-laying the males are 

 never found with the females, and where they remain is unknown ; the 

 period of egg-laying covers many hours, and probably, in some cases, 

 days. 



Structure of Eye of Frog.§ — D. Tretjakoff gives with considerable 

 detail an account of the structure of the anterior region of the frog's 

 eye. In the triangular chamber are two protractor lens-muscles and 

 two tensors of the choroid. The protractors affect materially the form 

 of the chamber, of the ciliary body, and the vascular distribution of the 

 episcleral net. These vessels are arranged so that the main mass of 

 arterial blood streams to the dorsal section of the annulus pericor- 

 nealis ; the main mass of venous blood flows in the ventral section. 

 The iris of the frog is distinguished by the presence of the " pupilar 

 knot," a derivative of the cavity of the eye vesicle ; in the adult this 

 contains a thickened modified stroma : in the embryo it is a purely 

 epithelial formation. 



* Tijdschrift Nederland Dierk. Ver., ix. (1905) pp. 1-144 (5 pis.). 



t Ber. Kiew Nat. Ges., xvii. See also Physiol. Russe, iv. (1905) p. 64. 



t Amer. Nat., xl. (1906) pp. 123-36. 



§ Zeitschr. wiss. Zool., lxxx. (1906) pp. 327-410 (3 pis. and 19 figs.). 



U 2 



