226 The Crab Parasite, Sacculina. [ March, 
but occurs on the ventral surface of the abdomen of its host 
The scientific genus-name of our parasite is Sacculina, and by 
calling it specifically Sacculina panopei, we honor both parasite 
and host. In systematic zodlogy this Sacculina belongs to the 
family Rhizocephala, and these again are classified among the 
barnacles or cirripeds, which the earlier zoologists regarded a 
mollusks, but which, in reality, are crustaceans and relatives of 
the lobster, shrimp and crab. Sacculina is one of the most 
striking examples of animal degeneration. Fig. 3 illustrates the 
r 
EXPLANATION OF FIGURES. ` tral view: cole 
FIG. 1.—Sacculina panopei, female enlarged (male unknown). Ven 
brownish. 
¢, abdominal, sub-segmented portion. 
6. thoracic portion, the sac filled with eggs. s 
a, pdomen of 
ai, \ the last three segments of ventral surface of a 
herbstii, 
Fic, 2.—Sacculina panopei, female, enlarged. Lateral view. 
a, abdomen of Panopeus herbstii. 
¢, abdominal portion with sexual orifice. 
Fic. 3.—Nauplius stage of Sacculina purpurea. (After Fritz 
Fic. 4.—Pupa stage of Lepas australis. (After Darwin.') 
*Chas. Darwin, A monograph of the sub-class Cirriped 
Miiller-) 
PTE eae 
