io6 Invertebrate Zoology. 



the gills. Do you find the external openings of the oviducts ? 

 Of the vasa deferentia ? 



Draw the animal as seen from above. 



Remove the lower portion of the left thoracic pleuron, 

 and expose the bases of the appendages. PodobranchicB 

 and arthrobranchice are not present. Are there flabella at 

 the bases of the ambulatory appendages ? 



Carefully remove the third maxilliped of the left side. 

 Compare it with the same of the lobster. 



Draw. 



The second maxilliped will be found to have endopodite, 

 exopodite, and flabellum, of the same general structure as in 

 Ho mar us. Only two gills are present. 



Draw. 



The first maxilliped is foliaceous and gill-less. Note its 

 greatly elongated flabellum, which extends far back into the 

 branchial chamber. 



Remove the appendage and draw. 



Examine the right (uninjured) side, and see if you do 

 not find at the base of the first maxilliped, and extending 

 anteriorly, a large opening that leads from the branchial 

 chamber. 



The second maxilla, as in the lobster, has a specially de- 

 veloped flabellum for bailing the water out of the branchial 

 chamber. Note how its protopodite is divided almost pre- 

 cisely as in Homarus. The rudiment of the endopodite is 

 especially interesting. 



Draw. 



Remove \htfirst maxilla and draw, and do the same with 

 the mandible. 



Examine the antenna, and see which are first and which 

 second. 



