ON THE ANASPIDACEA, LIVING AND FOSSIL. 505 
dacea, although agreeing essentially with that of the Decapoda, 
differs from the latter in responding to stimuli from the 
external world, as well as to internal stimuli set on foot by 
the position of orientation. 
The second antenne consist of a two-jointed protopodite, 
which supports an exopoditic scale and a flagellate endopodite. 
The scale is comparatively small in Anaspides (text-fig. 6) 
TEXT-FIG. 9. 
YY) 
Anaspides tasmaniz. Mandible. 
aud the fossil forms; it is considerably enlarged in Paran- 
aspides (text-fig. 7), probably in correlation with the 
swimming habit, and is altogether absent in Koonunga 
(text-fig. 8). The typical form of this antenna with its 
exopoditic scale and flagellum is characteristic of the 
“ Schizopoda” and Decapoda. 
The mandible in Anaspides tasmanize (text-fig. 9) 
