Fig. 6. Acidaspis trentonensis Walcott. Both the specimen, No. 245, and the photograph are poor, but show that in this genus the endopodites are like those of Triarthrus. × 8.5.
Fig. 7. Cryptolithus tessellatus Green. Specimen 234. This specimen shows well the backward directed antennules and also the outer segments of some of the cephalic endopodites. × 11.
PLATE VI.
HELIOTYPE CO. BOSTON