232 ON THE TRACHEA IN THE " RAT1TE " BIRDS. 



with the addition, in each case, of Garrodia, included by both authors in 

 the restricted genus Procellaria. 



Being now engaged in a report, for the Voyage of H.M.S. ' Challenger,' 

 on the anatomy of the Petrels collected during that expedition, I propose 

 to reserve further details of the differences and characters of these two 

 groups, and of the genera composing them, till that occasion. 



P. z. s.1881, 41. ON THE CONFORMATION OF THE THORACIC END 

 P- 778. TRACHEA m THE RATITE" BIRDS.* 



IN the present communication I propose to follow out the line of work 

 developed by the late Prof. Grarrod in his paper on the trachea of the 

 Gallinse t, by describing in detail the structure of the bifurcating trachea 

 in the " Eatite " birds. 



So far as I am aware, no proper description of this structure in the 

 birds in question has ever been given, though the statement, apparently 

 originally due to Meckel , that in them " there is no lower larynx," has 

 been very generally followed and copied, even in the latest text-books on 

 the subject . Prof. Owen has briefly described the bifurcating trachea 

 in the Ostrich || and Apteryx ^[ ; and his accounts, as far as they go, are 

 accurate enough. More recently E. Alix has very briefly mentioned 

 some peculiarities of this part in the Ehea; and his account will be 

 found quoted below. 



P. Z. S. 1881, Struthio camelus (figs. 1, 2), on account of its size and simple structure, 



p. 779. m ay be described here first. The trachea, inferior to the insertion of 



the sterno-tracheales, slightly narrows, having above the antepenultimate 



P. Z. S. 1881, ring a diameter of about one inch. The tracheal rings are here, as 

 p. 780. elsewhere, entire simple rings, of an average depth of about *15 inch, and 

 are separated only by very slight interannular intervals. The trachea is 

 slightly compressed and posteriorly carinated for about the last 7 rings. 

 The last ring but four is somewhat produced downwards in the middle 

 line, both anteriorly and posteriorly; it is, in consequence, narrower 



* Proc. Zool. Soc. 1881, p. 778-788. Read June 21, 1881. 



t " On the Conformation of the Thoracic Extremity of the Trachea in the Class 

 Aves. Part I. The Galling," P. Z. S. 1879, pp. 354-380. 



\ ' Trait< general d'Anatomie comparee,' x. p. 571 (1838). 



Cf. Huxley's 'Anatomy of Vertebrates,' p. 313; Macalister, 'Morphology of 

 Vertebrates,' p. 161. 



|| ' Catalogue of the Physiological Series of the Museum of the Royal College of 

 Surgeons,' ii. p. 1C3, prep. 1159 (1834). 



^[ Trans. Zool. Soc ii. p. 279. 



