| OCR Text |
Show 1896.] , OBLIQUE SEPTA IN THE PASSERINES. 229 as I have examined-both Acromyodian and Mesomyodian it should be observed-to the peculiarity which they show in the arrangement of the oblique septa. Another distinctive feature of Passerine anatomy is quite desirable. So far as w e know at present, there is positively only one character which is absolutely distinctive of Passerine birds. That is, in the condition of the tendon of the patagialis brevis muscle as it was described some years since by the late Prof. Garrod L. Though it is perhaps easy enough to define the Passeres by a combination of characters, none of these characters are everywhere present. It is therefore of more importance than in some easily definable groups to add to this single character only wanting in the Pseudoscines (Menura and Atrichia) another which future research may possibly show to be more universal, and which is at any rate found in several genera widely separated from each other. Fig. 3. Abdominal and thoracic viscera of Rook displayed by removal of abdominal muscles. St., stomach; L., liver; O.S., oblique septa. The lobes of the liver are covered by a membrane continuous with the dorsal part of the oblique septa. This anatomical feature may therefore have a considerable systematic interest. Apart, however, from this, which requires still further proof, the conditions which obtain in the Passerine bird remind one in some degree of the Crocodile. The liver-lobes 1 Coll. Papers, p. 356. |
