REPORT ON THE STOMATOPODA. 



19 



inner is always longest in Alima. In Erichthalima they are equal, and Ijotli ver}- short, 

 as is also the case in some of the more primitive Lysiosqidllse, and in Protosquilla. 



It will thus be seen that Erichthalima has certain characteristics which are found 

 nowhere else except in Alima or Squilla, and others which are found nowhere else except 

 in Lysioerichthus or Li/sios(juiUa, and others which are common to both, and others 

 which are found iu neither. Wc must therefore regard it as a more primitive larva than 

 either, equally related to both. 



In the Lysioerichthus series we have forms which, like Alima, have the rostrum and 

 postero-lateral spines long, and others which have them short. And in the Alima scries 

 we have Alimerichthus which has its carapace deep and its telson wider than lonw, as in 

 Lysioerichthus, while the carapace is flat and the telson longer than wide in all the other 

 Alim^. 



The relationship between these various larvae may then be expressed in a diagram as 

 follows : — 



Alima. 



Lysioerichthus with short si)ine.«. 



Alimerichthus. Lysioerichthus with long spines. 



Uric/if /laliiHu. Pseuderichthus. Gonerichthus. 



Unknown Ericlitlwidi7ia-]ike larva. 



This classification exactly matches the one given for the adult Stomatopoda on 

 page 12, and, added to the fact that the few larvae which have been traced to their 



