PRANIZA. :241 



of motion, like those of the Decapoda. Mr. Halliday in- 

 forms us that the young Pra?iizasn'e of the same form as the 

 adults. 



Bisso 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 Phi/sis tinea, a species of fish. Both these Pra- 

 nizce 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. Xat. Hist. v. 521, f. 99. 



R 



