BY W. J. MACKAY, B.SC. 9 GO' 



led me to enquire whether the structures above described might 

 not represent this part of the limb in an abortive form and with 

 its position altered ; but exopodites of the ordinary form are, as I 

 have ascertained, entirely wanting also in Aslacopsis in which the 

 inter-coxal lobes are highly developed ; the latter cannot 

 therefore be transformations of the ordinary exopodites ; nor can 

 they be exopodites which are abortive from the outset, since in 

 Homarus, in which they are highly developed, the larva when 

 hatched has exopodites of the ordinary form attached at the basi- 

 ischiopodite joint. 



