ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 429 



t'orenamed cells and which presumably unite with them. In the process 

 of development there is an evident stimulus towards the formation of 

 a fibrillar net from the granular content of the protoplasm of the sense- 

 cell. 



Eye of Spalax typhlus.* — J. Szakall describes the degenerate eye 

 of this " blind mouse." There is no eyelid opening ; the eye lies in a 

 closed conjunctival sac ; and the light can only enter through the skin. 

 All the essential parts are present, but they remain undifferentiated. 

 Thus the anterior and posterior basal membranes are lacking in the cornea ; 

 the choroid is not separated from the sclerotic ; the ciliary bodies are 

 wholly due to folds of the pigment layer of the retina ; the retina is 

 relatively undifferentiated ; the lens is a mass of irregular cells, under- 

 going disruption ; the anterior wall of the lens is directly apposed to 

 the posterior surface of the cornea ; the arteria hyaloidea, as an 

 embryonic vestige, is always demonstrable ; the eye-muscles are quite 

 absent, but the Harderian gland is unusually large. 



Relationships of the Tarpan.f — J. Cossar Ewart concludes that the 

 Tarpan, once common in the east of Europe, cannot be regarded as a 

 true wild species. It may be assumed that the Tarpan herds were 

 derived from at least three primitive stocks, viz. (1) from a variety or 

 species identical with or closely related to the wild horse (Equus 

 prejvalskii) still surviving in Central Asia ; (2) from a variety having 

 the characteristics of the Celtic pony (E. c. celticus) ; and (3) from a 

 variety resembling the forest horse {E. c. typicus). The variety of 

 characters seen in the Tarpans suggests this multiplex origin. Experi- 

 ments in progress may settle what part Prejvalsky's horse had in 

 forming the Tarpan. The author adheres to his general view that 

 domesticated horses have had a multiple origin, and include plain as 

 well as striped forms amongst their less remote ancestors — have not, in 

 fact, as Darwin thought, descended from a single dun-coloured, more or 

 less striped, primitive stock. 



Arrangement of Bronchial Blood Vessels.! — W. S. Miller gives 

 an account of the arrangement of the vessels in the bronchi and their 

 relation to the pulmonary vessels. They are directly connected with the 

 pulmonary vein, and can be only partially injected from the pulmonary 

 artery when the pulmonary vein is clamped, and then by a backward 

 flow along the venous radicles which arise from the bronchi. 



Cranial Nerves in Chick.§ — F. W. Carpenter gives an account of 

 the anatomy, histology, and development of the oculomotor nerve, the 

 miliary ganglion, and the abducent nerve in the chick. There is also a 

 discussion of the migration of the medullary cells, the histogenesis of the 

 neuraxons, the nature of the ciliary ganglion, and the homologies of the 

 ■oculomotor and abducent nerves. 



* Math. Nat. Ber. Ungarn., xx. (1905) pp. 272-88 (5 figs.). 



t Proc. Roy. Soc. Edinburgh, xxvi. (1906) pp. 7-21 (3 pis. and 2 figs.). 



X Anat. Anzeig., xxviii. (1906) pp. 432-6 (3 figs.) 



§ Bull. Mus. Comp. Zool. Harvard, xlviii. (1906) pp. 141-229 (7 pis.). 



