256 MK. F. J. COLE OK THE DEVELOPMENT OF 



Fig. 5. Left wing, dorsal aspect, of an adult Asio accipitrinus, to show the 

 typical, adult, diastataxic wing. Note the absence of a remex between 

 the 5th pair of major coverts, and the marked gap between the 4th 

 and 5th remiges. 



Plate 15. 



Fig. 1. Eight wing, dorsal aspect, of an embryo Columba domestica. This is 

 markedly diastataxic. The shifting of the coverts is very distinct. 

 Compare PI. 16. fig. 1. 



Fig. 2. Right wing, dorsal aspect, of an embryo Lomvia troile, at present 

 eutaxic ; but a study of the coverts shows that a shifting has com- 

 menced, the result of which ultimately reduces the wing to the typical 

 diastataxic form. Compare this with the figure on p. 243, which 

 shows the condition of the wing in the downy nestling. 



The figure immediately below is drawn from fig. 2 to show the 

 effect of a slight increase in the shifting' of the^coverts transforming 

 the wing from the eutaxic to the diastataxic type, as seen in fig. 1. 



Fig. 3. Eight wing, dorsal aspect, of an embryo Anas hoscas, var. domestica, 

 decidedly diastataxic. No earlier stages were procurable. 



Plate 16. 



Fig. 1. Eight wing, dorsal aspect, of a nestling Columba domestica. Note the 

 intercalary row of coverts, and compare with fig. 1, PI. 14. ; also ther 

 large size of the major coverts of the forearm as compared with the 

 cubital remiges (1st c.r.), which have as yet only just begun to project ■ 

 beyond the surface of the wing. 



Fig. 2. Eight wing of adult Opisthocomus. 



On the Discovery and Development of E-habdite-" cells " in 

 Gephalodiscus dodecalopTius, Mcintosh. By|F. J. Cole,^ 

 University College, Liverpool. (Communicated by Prof, 

 G. B. Howes, Sec. Linn. Soc.) 



[Read 6th April, 1899.] 



(Plate 17.) 



A SHORT while back Professor Herdman was kind enough to 

 place in my hands some small pieces of Cephalo discus for treat- 

 ment and sectioning by modern microscopical methods. As 

 interest in this unique form has been again aroused by the 

 recent work of Masterman *, it was proposed to revise the whole 

 anatomy of the polypide besides investigating the few points 

 which a consideration of the literature showed to be unsettled, 



* Q. J. M. S. vol. xl., 1897 ; Trans. E. S. Edin. vol. xxxix. pt iii., 1898. 



