NO. 9 



MUSCULATURE OF THE BLUE CRAB COCHRAN 



69 



ones (/pp b) are inserted just below the inner end of the exopyloric 

 ossicle (IV) near the end of the propyloric ossicle (VI), while the 

 external pair (/pp a) are inserted on the outer half of the exopyloric 

 ossicle (VI). The outer and inner posterior gastric muscles seen in 

 their natural positions resemble the spokes of an opened fan, being 

 nearly alike in size and length and converging at somewhat similar 

 angles to their respective points of insertion. (Figs. 29, 30.) 



2 3 197 



— 200 



204a 204b 198 199b 199a 



Fig. 29. — Muscles of the stomach viewed from above. 



7p7, musculus gastricus anterior ; 198, musculus gastricus posterior mesalis ; 

 199a and b, musculus gastricus posterior lateralis a and b; 200, musculus dila- 

 tator anterior superior ventriculi ; 204a and b, musculus dilatator dorsalis pylorici 

 anterior a and b; 2iua and b, musculi cardiopylorici a and b; 213, musculus 

 cardiacus anterior mesalis ; 214, musculus cardiacus anterior lateralis. 



The following muscles dilate the stomach : 



200. Musculus dilatator anterior superior ventriculi. One pair. — 

 Each muscle arises from the inner side of the cervical membrane im- 

 mediately behind the orbit. The body of the muscle extends inward 

 and backward, dividing very soon into a dozen or more slender fibers 

 which diverge widely to their points of insertion at various places on 

 the anterior upper and outer walls of the stomach. These fibers are 

 exceedingly delicate. (Figs. 29, 30.) 



