Bull. U S. B. F., igog. 



Plate XXXVIII. 



SS '" 



clbr. 



Fig. 4- 



Figs. 1-4. — Left second to fifth pereiopods or slender legs of adult lobster from anterior side, showing numbered segments of per- 

 manent limb, distribution of sensory tufts {s s), gills (/■*. infig. 1-3). and gill separators (e/>), arrangement of ball-and-socket 

 basal hinges, median ball (A, 6), and peripheral socket (A, .r), tendons of basal joints {.i.fl. i, and t. ex. i), and cleaning pick 

 and brush (cl. br) of last leg. Starinfigure 4 marks position of exopodite or outer swimming branch of thoracic limb, shed at 

 fourth stage. 



