ON THE ANASPIDACEA, LIVING AND FOSSIL. 517 
The presence of this spermatheca is of considerable taxo- 
nomic importance, as it appears to be entirely absent in the 
other Schizopods, viz. Mysidacea and Euphausiacea, but to 
TEext-FIG. 2o. 
Paranaspides lacustris. Eighth thoracic limb. 
be present in certain of the more primitive Decapods. In 
the lobster and certain prawns a similar spermatheca is 
TEXT-FIG. 26 
AS ye 
Paran spides lacustris. Basal segment of eighth thoracic 
limbs, showing male openings. 
present, and in the peculiar Eryonidea (Polycheles, 
Willemcesia) the presence of a spermatheca in the same 
position was pointed out to me by Mr. Gray, of the Oxford 
