THE CRAYFISH. 



PLATE VIII. 



THE CBAYFISH.f THE EXOSKELETON AND APPENDAGES. THE MUSCULAR SYSTEM. 

 FIG. I. The entire animal, from the left side, in the resting attitude ?. Nat. size. 



FIG. II. The same from beneath, all the appendages of the left side and a portion of 

 the branchiostegite having been removed, in order to display the whole sternal surface. 



The last ambulatory leg is drawn in its functional position, as the chief lever in forward 

 progression. The feeler of the antenna is indicated as underlying the chela, in error. Nat. 

 size. 



FIG. III. Median vertical-longitudinal section of the same, the soft parts having been 

 removed, after boiling in 10 p.c. potash solution. Nat. size. 



FIG. IV. Transverse section of the thorax, taken immediately behind the bases of the 

 great chela?, treated as in Fig. III. 



The small ingrowths marked thus * give part attachment to the levator muscles of the 

 fore-gut, and may be appropriately termed endotergites. x 2. 



FIG. V. The third abdominal segment of the ? , seen from behind. 

 On the left side the parts are represented in section, for purposes of comparison with 

 Fig. IV. x 2. 



FIGS. VI. to XXII. The appendages. AH x 3. 



Only the typical ones are drawn. Taking the second maxillipede (Fig. VI.) as a 

 central type, the others are represented in series, the divergent lines of which are indicated 

 by arrows. 



All are drawn in the relatively natural position, their posterior surfaces being alone 

 represented. 



VII. A portion of the third maxillipede, to show the fusion of the ischiopodite and 

 basipodite, characteristic of it and the great chela. 



VIII. The penultimate ambulatory appendage. 



IX. The two terminal joints of the first ambulatory leg. 



X. The gill-bearing portion of the Lobster's third ambulatory appendage. 



XI. The first maxillipede of the Crayfish. 



* All the figures of Plates VIII. to X., unless otherwise stated, refer to the Red-footed French Crayfish (.Is ociw 

 iatilis, var. nobilis), specimens of which can often be obtained in our English markets 5 to inches in length. 



