27 



PLATE XIV. 



LOBSTER AND CRAYFISH— cm^^med 



(( 



Alimentaey System — 



Fig. 1. Stomach in Elevation and Plan — 



,, . , , f Anterior or cardiac. 



Posterior or pyloric, the anterior part of which i.s the prepyloric. 



ri T ■ T -if Transverse piece. 



, Cardiac region — cardiac ossicle -{ ,^ ,. ^ ,. , 



a, J ( urocardiac process, a median prolongation. 



I Prepyloric region — median prepyloric ossicle (green). 



V> Pyloric region — transverse pyloric ossicle. 



Figs. 2, 3, i. Detailed Structuee of Gastric Skeleton — 



Ossicles — 



Cardiac, with urocardiac process. 



Prepyloric (lig. -t). 



Pyloric (fig. i). 



Lateral i ^^t^''''"' P"'"' (^H^- ^ '"^'^ ■^)- 

 ( Posterior pair. 



Teeth of— 



Lateral posterior ossicles. 



Prepyloric ossicle — a single median tooth. 



CiRCTILATOEY AND RESPIRATORY SYSTEMS 



DiAG. 1. Circulatory and PiEspieatory Organs — 



Heart, rhythmically contractile and systemic — that i.?, it propels the blood received from the gills 



through the system. 

 Pericardium, a cavity surrounding the iieart. 

 Arteries carrying the blood to — 



Eye, ophthalmic. 



Antenna, anteunary. 



Kest of body, sternal with -f ^"f "°^' abdominal branch. 



I Inferior abdominal branch. 

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

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

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



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

 from venous sinus, and a descending blnod-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. 



. I 2 Anteiniarv. 



Arteries • • • • s „ ,t /^ , , ,• % 



2 Hepatic (Gr. hcpar, hcpatos, the liver). 



. 1 Sternal, with its superior abdominal branch. 

 ( 2 Superior. 

 Vaivuxar Apertures < 2 Lateral. 

 (, 2 Inferior. 

 Pericardial cavitj^, so-called pericardium. 

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



