PLATE XXIII. 



Class CRUSTACEA 



THE LOBSTEK continued. 



FIG. 1. EYE, EAR, AND GREEN GLAND, x 1. 



r. rostrum : e. eye : a. o. auditory opening on the basal joint of the 

 antennule : a. antenna : b. bristle passed into the opening of 

 the green gland : g. green gland : s. its sac. 



FIG. 2. MOUTH PARTS, x 1. 



inn. mandible : p. palp : t. tendon : m. mouth : 1. labrum : ms. 

 metastoma. 



FIG. 3. STOMACH OPENED FROM ABOVE, x 1. 



0. gastric ossicles. 



FIG. 4 FOURTH ABDOMINAL SOMITE : POSTERIOR VIEW, x J. 



t. terguin : p. pleuron : s. sternum : pr. protopodite : ex. exopodite : 

 en. endopodite. (The portion, scarcely distinguishable in this 

 segment, between the base of the protopodite and the pleuron 

 is the epimeron.) 



FIG. 5. THIRD MAXILLIPED. x 1. 



p. protopodite : en. endopodite : ex. exopodite : g. gill : ep. epipodite : 

 i. ischiopodite : m. meropodite : c. carpopodite : p. propodite : 



d. dactylopodite. 



FIG. 6. GILLS EXPOSED BY REMOVAL OF THE BRANCHIOSTEGITE. x 1. 

 g. gills : e. epipodite. 



FIG. 7. TRANSVERSE SECTION OF THE THORAX, TO ILLUSTRATE THE RESPIRATORY 

 CIRCULATION, x 1. 



1. leg : v. s. venous sinus : g. gill : a. afferent branchial vessel : 



e. efferent branchial vessel : s. sternal artery. 



