igo5 .] ANATOMY OF PHAL^NOPTILUS, RIDGWAY. 223 



approach the humerus. The muscle inserts upon the humerus be- 

 tween the pars scapuli-cubitalis and the pars humero-cubitalis near 

 the lower point of the humeral crest. 



The posterior part (Zat. d. p.) comes from the last dorsal verte- 

 bra and the anterior rim of the ilium. The fibers converge rapidly 

 as they pass anteriorly, and find their insertion on the humerus 

 beneath the anterior border of the above. 



4. M. rhomboideus superficialis (Rh. s., PI. V, Figs. 17, 22). 

 This flat muscle comes from the last two cervical vertebrae and the 

 following dorsal vertebrae. It is inserted fleshily on the dorsal 

 part of the furcula and on the entire dorsal border of the scapula. 



5. M. rhomboideus profundus {Rh. p., PI. IV, Fig. 17). This 

 muscle is covered by the last mentioned muscle and by the pos- 

 terior portion of the latissimus dorsi. It springs fleshily from the 

 last cervical and first dorsal vertebrae. The outward directed fibers 

 find a fleshy insertion on the posterior half of the dorso-median 

 border of the scapula, the insertion being continued down to the 

 posterior tip of this bone. 



6. M. scapuli-humeralis anterior. This muscle is absent. 



7. M. scapuli-humeralis posterior (Sc. hum. p., PI. V, Figs. 17, 22; 

 PL III, Fig. 26). This large, somewhat rhomboidal-shaped muscle 

 comes from the outer surface of the posterior two thirds of the 

 scapula. It is covered by both portions of the latissimus dorsi. 

 Its fibers are directed forward and downward, converging rapidly 

 to form a small, round bundle which is attached within the fora- 

 men pneumaticum. 



8. M. subscapularis (S. sc, PI. VI, Fig. 26). This muscle 

 becomes visible after the removal of them, scapuli-humeralis poste- 

 rior and m. scapuli-cubitalis. Anteriorly it comes from the dorsal 

 surface of the scapula just posterior to the origin of the scapuli- 

 cubitalis, and posteriorly from the lower border of the same bone 

 where it is overlain by the scapuli-humeralis posterior. In its 

 middle portion it is divided into two parts by the anterior m. ser- 

 ratus superficialis, the inner division, subscapularis internus, coming 

 from the ventral surface of the scapula. The outer portion is the 

 subscapularis externus. 



9. M. serratus superficialis (PI. VI, Fig. 26) is made up of two 

 parts. The smaller anterior division (Ser. s. a. ) comes from the last 

 cervical rib and its process uncinatus. The fibers are directed upward 



