ENTOZOIC COPEPOD FROM JAPAN. 227 
GOIDELIA JAPONICA, Nov. gen. et sp. 
Diagnosis of Generic Characters.—Body flattened, segmented, 
and cyclopoid ; sexes equal in size, dimorphism only being 
apparent on closer examination of the appendages; the male not 
attached to the female ; no eyes. 
1st antenna alike in female and male ; composed of 5 segments. 
2nd antenna alike in female and male; composed of 4 segments, 
forming a characteristic elbow ; the three terminal segments con- 
stitute a powerful hooking apparatus. 
Mandibles alike in female and male; very small and claw- 
like; with xo accessory parts (such as occur in the other known 
genera). 
lst maxillipede Q differs much in the immature stages; in 
the adult it is a claw-like organ with two recurved hooks (in the 
other genera this appendage is alike in both sexes, being very 
highly developed). 
lst mazillipede 3 alike in all stages; very degenerate, being 
only a fringed plate. 
2nd maxillipede Q alike in all stages; very degenerate, being 
only a papilla (Gn the other genera this appendage shows sexual 
dimorphism, but in both sexes it is very highly developed). 
2nd maxillipede 3, different in the various stages; very 
specialized as a powerful chela (in the other genera there is no 
suggestion of a chelate apparatus). 
Thoracic legs 1-4 all alike; biramous; no sucking-discs (such 
as occur in the other genera, where also the Ist leg is unlike the 
others). 
Thoracic leg 5 uniramous in female and male. 
Abdomen of 6 segments ; in the female the first three are fused. 
Furce show no difference in male and female; each furca 
bears a long and a short seta. 
TRICHODINA (n. sp.). (Pl. 22. fig. 20.) 
The rectum of Hchiurus unicinctus gives shelter not only to 
the parasitic Copepod Groidelia japonica, but also to a minute 
Infusorian: being so excessively small, this creature would in 
all probability have escaped my notice had it not occurred in such 
abundance. I first saw it in a series of transverse sections of 
the whole Echiurus, where it was very conspicuous in all sections 
of the rectum, for the methylene-blue which I was using as a 
double stain settled far darker in these little parasites than in any 
16* 
