72 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 92 



2og. Miisciilus dilatator posterior oesopJiagci. One pair. — This 

 muscle is small and not easily distinguishable, lying as it does within 

 the web of tissues surrounding the stomach. It arises on the endo- 

 pleurite of the first maxillary segment, passing backward and over the 

 inner ventral pyloric dilator (20 j b) to its insertion on the lateral 

 wall of the esophagus just posterior to the insertion of the lateral 

 dilator of the esophagus {208). (Fig. 30.) 



INTRINSIC MUSCLES 



210 a and b. Musculi cardiopylorici a and b. A median and two 

 lateral.- — The median muscle {b) extends from the thickened posterior 

 border of the mesocardiac ossicle (/) to the upper central edge of the 

 propyloric ossicle {VI). The lateral muscles (a) extend from the 

 mesocardiac ossicle (/) to the inner end of the exopyloric ossicle (IV), 

 diverging slightly posteriorly. These muscles oppose the movements 

 of the extrinsic gastric muscles. (Figs. 29, 30.) 



211 a-g. Musculi interiores cardiaci laterales a-g. Seven pairs. — 

 These muscles all run more or less dorsoventrally on the lateral wall 

 of the stomach. (Fig. 30.) In the following list, the dorsal insertion 

 is named first : 



a. Hammer-shaped ossicle in the posterolateral cardiac plate (Cd 

 PI) to the inferolateral cardiac ossicle (XI). 



b. Prepectineal ossicle {IX) to inferolateral ossicle {XI). 



c. Zygocardiac ossicle (///) to inferolateral ossicle {XI). 



d. Zygocardiac ossicle (///) to anterior supra-ampullary ossicle 

 (XX). 



e. Zygocardiac ossicle (///) to anterior supra-ampullary ossicle 

 (XX) ; perhaps this and the preceding should be considered as parts 

 of the same muscle because they have their origins and insertions on 

 the same ossicles, although not on the same points of the ossicles. 



/. Exopyloric ossicle (IV) to anterior pleuropyloric ossicle 

 (XXIII). 



g. Pyloric ossicle (VII) to anterior pleuropyloric ossicle (XXIII). 



212. Miisculus cardiactis posterior inferior. One pair. — This muscle 

 is composed of short fibers attached on the sides to the inferolateral 

 cardiac ossicle (XI) and coming almost together at the median line, 

 where they are attached to each side of a projecting ridge running 

 down the center of the cardiopyloric valve. These muscles cannot be 

 seen until the outer and inner lower dilators of the pylorus have been 

 removed, as well as the obscuring branches ni and n of the pyloric 

 muscle. (Not figured.) 



