i9°5-] 



ANATOMY OF PHAL/ENOPTILUS, RIDGWAY. 221 



are arranged in a somewhat circular fashion just posterior to the 

 external opening. On each side of the median ridge of the palate 

 is a long, narrow slit bounded by fimbriated folds of mucous mem- 

 brane, the internal nares. 



The pecten of the eye (Figs. 4, 5) consists of four folds. It 

 measures in height about 2 mm., and its basal breadth is about 

 1.5 mm. Like the choroid coat it is heavily pigmented. 



VI. Myology. 



Only muscles of the extremities have been considered, and in 

 naming them the terminology of Gadow (/. c. ) has been followed 

 as strictly as possible. There are, however, many deviations from 

 his definitions. 



1. Anterior Extremity. 



Here are described all the muscles of the wing proper, also all 

 coming from the shoulder girdle, ribs and vertebrae and inserting 

 upon the wing, also all the muscles inserting on the scapula and 

 coracoid. The metacarpals named by Gadow (/. c. ) I, II and III 

 are herein termed II, III and IV, for recent embryological investi- 

 gation show the first and fifth to be the ones lost. 



A. Pectoral Muscles. 



1 . M. pectoralis. The pars propatagialis and pars abdominalis 

 are absent. 



Pars thoracica {Pect., PI. V, Fig. 24; PI. VI, Fig. 25). 

 This is the large superficial muscle of the breast, and covers the 

 other breast muscles. It has an extensive origin, coming from the 

 clavicle and the membrane between that bone and the sternum ; 

 from the surface of the keel, the upper half; the posterior border 

 of the sternum ; and the posterior lateral portion of the breast bone. 



It has two points of insertion, both of which are on the humerus. 

 The short strong tendon which terminates on the ventral projection 

 of the humerus, just anterior to the biceps, is the posterior inser- 

 tion. The fibers of the anterior portion converge and pass ob- 

 liquely to the dorsal crest of the humerus and are there attached 

 fleshily. 



2. M. supracoracoideus {Sup. cor., PI. VI, Figs. 25, 30). This 

 is a double-feathered muscle arising from that portion of the coraco- 

 clavicular membrane not occupied by the muscle just described, 



