27 



PLATE XIV. 



LOBSTER AND CRAYFISH continued. 



ALIMENTARY SYSTEM 



FIG. 1. STOMACH in Elevation and Plan 



I'E 'IONS -f Anterior or cardiac. 



( Posterior or pyloric, the anterior part of which is the prepyloric. 



( Cardiac region-cardiac ossicle { T r ransverse P iece - 



SKELETON < ' ^rocardiac process, a median prolongation. 



} Prepyloric region median prepyloric ossicle (green). 

 V Pyloric region transverse pyloric ossicle. 

 FIGS. 2, 3, 4. DETAILED STRUCTURE OF GASTRIC SKELETON 

 Ossicles 



Cardiac, with urocardiac process. 



Prepyloric (tig. 4). 



Pyloric (fig. 4). 



Lateral j Anterior pair (figs. 3 and 4). 



( Posterior pair. 

 Teeth of 



Lateral posterior ossicles. 

 Prepyloric ossicle a single median tooth. 

 CIRCULATORY AND RESPIRATORY SYSTEMS 



DIAG. 1. CIRCULATORY AND RESPIRATORY ORGANS 



Heart, rhythmically contractile and systemic that is, it propels the blood received from the gills 



through the system. 



Pericardium, a cavity surrounding the heart. 

 Arteries carrying the blood to 

 Eye, ophthalmic. 

 Antenna, anteunary. 



Kest of body, sternal with { Su P erior ^dominal brand,. 



( Inferior abdominal branch. 



Veins, gather up blood and carry it to gills for aeration. 

 Branchio-cardiac canals, carry blood from gills to pericardium. 

 Valvular openings, by which the blood in pericardium enters heart. 



Gills, each consisting of a central stem with an ascending blood-vessel on its outer side leading 

 from venous sinus, and a descending blood-vessel on its inner side leading to branchio- 

 cardiac canals. The stem is beset with fine filaments which repeat the structure of the stem. 

 DIAG. 2. ELEVATION AND PLAN OF HEART 



( 1 Ophthalmic. 



ARTERIES -< 2 Antennar y- 



} 2 Hepatic (Gr. hr.par, hepatos, the liver). 



V 1 Sternal, with its superior abdominal branch. 



( 2 Superior. 

 VALVULAR APERTURES < 2 Lateral. 



(. 2 Inferior. 



Pericardial cavity, so-called pericardium. 

 Fibrous tissue, two pair of bands holding heart in place. 



