192 MR. A. H. GARKOD ON THE [Feb. 1, 



length, and fusiform in general outline. The sacculating bands are 

 not lateral, but on their outer and inner borders, being continued 

 from the longitudinal fibres of the large and the small intestine. 

 Their mucous membrane is not plicated when they are distended. 

 It is only, among other birds, in Struthio and Rhea that the caeca 

 are sacculated; in these, however, there is only a spiral twist like 

 that in the caecum of the hares and rabbits. 



Each csecum has a well-developed special sphincter muscle guard- 

 ing its aperture of communication with the intestine ; and what is 

 more peculiar still is, that they do not open into the colon proper, 

 but into a sjiecial cavity, a continuation of the main intestinal tube, 

 but separated off by a very constricting sphincter from the colon, as 

 well as by the ileo-caecal valve from the small intestine. This ileo- 

 colic cavity is | of an inch long and about k an inch in diameter 

 when undistended. Its mucous membrane is like that of the cseca, 

 much more delicate than that of the colon. The ileo-csecal valve is 

 a small slit-like opening, nearly \ of an inch long, with its lips pro- 

 jecting a little way into the ileo-colic cavity. The two openings of 

 the cseca into the same cavity are one on each side of it, a little 

 oblique in regard to it, and considerably larger in lumen. The 

 opening into the colon is very constricted ; beyond it the mucous 

 membrane of the large intestine is, as Dr. Crisp remarks*, trans- 

 versely plicated, to produce an appearance much like coarse valvulse 

 conniventes. 



Nothing like the above-described condition is to be observed in 

 any other bird, not even in Struthio or Rhea, in both of which, as 

 typically, the cseca enter the commencement of the uniformly cylin- 

 drical colon by fair-sized orifices, not surrounded by a special 

 sphincter. This being the case, I cannot agree with Prof. Parker's 

 remark f that "there is nothing whatever in the digestive organs, 

 which are extremely voluminous, to separate the bird from the 

 Geese." 



Respiratortj Organs. — Prof. Parker J remarks, " the trachea and 

 inferior larynx are truly anserine ; for there are no inferior laryngeal 

 muscles, the contractors of the trachea ending one third of an inch 

 above the bifurcation, and only a delicate fan-shaped fascia going to 

 the half-rings. Moreover the trachea itself, from being flat and 

 cartilaginous, becomes round and then compressed, and osseous an 

 inch above the bronchi, so that it cannot be mistaken for any other 

 than the trachea of an anatine bird." In that the lower end of the 

 trachea is of smaller diameter than is the tube higher up, in that in 

 the same part the constituent rings are in close contact without 

 scarcely any intervening membrane, in that there are two pairs of 

 tracheal muscles running to the thoracic parietes, and in that the 

 intrinsic lateral tracheal muscles end before they reach the bifurca- 

 tion of the bronchi, the syrinx of the Screamers approaches that of 

 some of the Anseres ; but in that there is no special modification of 

 the organ in the male, and in the absence of chondrification or ossi- 

 fication of what are generally present as dilating rings or half-rings 

 * P. Z. S. 18()4. p. 10. t P. Z. S. 18(i.S, p. 514. + Loc. cif. 



