OCR Text |
Show 1873.] ANATOMY OF STEATORNIS. 531 an inch long, slender and quite blended with the palatines ; its anterior pointed extremity advances as far forwards as the posterior border of the median palatine symphysis mentioned above. The posterior external angles of the palatines, so large in Caprimulgus and Podargus, are not developed. The basipterygoid facets are large. In the eye the sclerotic ossifications are not considerable, as in the Owls, being not at all unusually developed. In the atlas the cup for articulation with the occipital condyle is incomplete behind; and the odontoid process of the axis is situated near its posterior margin. In this conformation, the classificational importance of which was first pointed out by M r . Parker, Steatornis agrees with the Strigidae and the Caprimulgidae, but not with the Cypselidae, in the one or two cases which I have had the opportunity of observing. The well-known peculiarities of the sternum do not seem to point definitely in any special direction ; and in the other bones 1 have not observed any demonstrable tendencies. Digestive organs.-The tongue is thin, smooth, and triangular ; it is \ inch broad at its base, and -| of an inch long; the posterior angles are prolonged backwards for \ of an inch as angular processes with small papillae on them ; the posterior border is simple. The oesophagus is capacious and uniformly cylindrical, with longitudinal plications in its mucous membrane. The proventriculus is zonary and well developed, the largest of its component glands, which are slightly racemose, being -| of an inch long. The stomach forms a thin-walled, globose, capacious gizzard, with its mucous membrane, as usually, longitudinally plicated. The intestines are 22 inches long, capacious throughout, and especially so near the pyloric portion ; the biliary and pancreatic ducts open into it 2\ inches from the pylorus, at the bend of the duodenal loop. The two intestinal caeca are lj and 1\ inch long, slender, and a little broader at the caecal than at the open ends ; they are situated 2 inches from the cloaca. The trachea is a little more capacious above than below. As in many birds, the separate rings of which it is composed are not so deep in the middle line as they are laterally; and as in each ring the upper and lower margins of one side in one ring, and of the other side of the next above and below, are slightly everted, whilst those of the other half are inverted to the same extent, when the rings are superimposed they produce the appearance seen in the accompanying drawing, as if each ring were narrow on one side and broad on the other. The syrinx (fig. 3, p. 532), as has been described by others, is extremely peculiar, because it is formed in each bronchial tube, instead of at the bifurcation of the trachea. The trachea bifurcates at its lower end m u c h in the same way that it does in Mammalia; and each bronchus continues down towards the lungs as a cylindrical or slightly flattened tube, composed of simple and entire rings of cartilage. In a specimen that I once saw, there were fourteen of these rings on each side; but in the one before me, which is figured here, the bronchi are not equal in length, the left bronchus containing 34* |