PRANIZA. 
241 
of motion, like those of the Decajooda. Mr. Halliday in- 
forms us that the young Praniza are of the same form as the 
adults. 
Risso has described two Mediterranean species (H. N. 
Eur. Mer. v. 83). One of these lives in numbers in the in- 
terstices of madrepore tufa, formed at great depths in the 
sea; it is an active species, and sometimes fixes itself to the 
gills of the Phy sis tinea , a species of fish. Both these Pra- 
niza usually cling to seaweeds and corallines, and when they 
leave them, they swim with great quickness, and being 
very nimble, elude the grasp of any one who tries to catch 
them. 
Praniza fuscata, Johnston.^ — Abdominal segment red- 
dish-brown, two lines long, subcylindrical. Head, thorax, 
tail, and legs colourless and transparent ; eyes black, great 
segment of a reddish-brown. Head pointed. Antennae 
lateral, four-jointed, the ultimate joint long and divided by 
many transverse lines. Eyes lateral, large, compound, like 
those of insects. Thoracic segments very small, with a pair 
; of legs to each; abdomen ovate, with a translucent edge, 
| furnished with three pairs of legs, one from the anterior 
|| margin, one from the middle, and one from a projecting 
* Mag. Nat. Hist. v. 521, f. 99. 
R 
