144 MORPHOLOGY OF INVERTEBRATE TYPES 



the cardiac ossicle and with the prepyloric ossicle or median 

 tooth. The cardiac ossicle is at each end (i. e., on the right and 

 left) articulated with the base of the pterocardiac ossicle. To- 

 gether they form a sharp point. The pterocardiac ossicle is 

 more or less triangular in shape and its apex articulates with the 

 zygocardiac ossicle. The thickened edge of the latter extends to 

 the edge of the pouch. Here it articulates with a small triangular 

 ossicle the anterior dorsolateral pyloric plate which thus serves 

 to connect the zygocardiac with the pyloric ossicle. Below the 

 upper edge of the zygocardiac ossicle is a lateral pouch with 

 several dark brown notches. These are the lateral teeth which 

 project into the stomach and form a part of the zygocardiac 

 ossicle. A rod-like ossicle the posterior intermediate cardiac bar 

 runs from the lateral pouch of the zygocardiac ossicle ob- 

 liquely downward. At its lower end it articulates with two 

 closely applied ventrolateral cardiac bars. These bars seem at first 

 sight to form a single ossicle and have the appearance of a curved 

 sabre. At the anterior end the two bars articulate with a single 

 anterior lateral cardiac bar which appears almost as a continua- 

 tion of the other two. Between the articulation point of the 

 zygocardiac with the pterocardiac ossicle and that of the pos- 

 terior intermediate cardiac bar with the ventrolateral cardiac 

 bars are two ossicles or intermediate cardiac bars articulating with 

 the small inferolateral tooth. A narrow curved ossicle the 

 gastrolithic bar runs forward from the apex of the pterocardiac 

 ossicles. The remaining ossicles (the number of the various 

 ossicles in the stomach is twenty-four and of these several are 

 paired) are more difficult of observation and may be omitted. 

 Make a drawing of a side view of the stomach and label all parts. 

 26. Open the stomach in the mid- ventral line. Make a draw- 

 ing of it showing cardiac sac, pyloric sac and gastric mill, con- 

 sisting of the median tooth, lateral teeth and small inferolateral 

 teeth. 



