ON THE ANASPIDACEA, LIVING AND FOSSIL. 51 
Koonunga the palp is still more developed, and the lower 
biting blade is reduced, being tipped with only three sete. 
The second maxilla (text-figs. 15, 16, 17) has a very 
uniform structure in the three genera. It may be interpreted 
as consisting of four gnathobasic lobes, a palp which has taken 
on the function of a gnathobase, and an exopoditic lobe, which 
is well developed in Paranaspides, much reduced in Anas- 
pides, and absent in Koonunga. 
The structure of this maxilla resembles that of the Mysi- 
TExtT-FIG. 19. 
Paranaspides lacustris. First thoracic limb. 
dacea more closely than that of the Euphausiacea, especially 
in the distinctness and arrangement of the gnathobases. 
Among the fossil forms the structure of the mandibles and 
maxille has not been elucidated. 
The first thoracic limb (text-figs. 18, 19, 20) differs 
only in detail from those of the following segments. It con- 
sists of a pediform endopodite with a reduced lamelliform 
exopodite. In Anaspides and Paranaspides the limb is 
composed of eight distinct segments, a protopodite of two 
joints and an endopodite of six. The coxopodite in both forms 
