PHRONIMA ATLANTICA. 
331 
nautilus, nor is there any keel to- constitute it an 
Atlanta — it is a recent Beleropliina ! 
Although it is perfectly true of tlie large-headed 
transparent shrimps comprising the family Phrono- 
midm that they are more or less parasitic, being 
found stowed away in the pouches and other 
cavities of the equally pellucid Acalepha?, yet some- 
times they swim freely about, and are frequently 
taken in the towing-net. I have obtained a speci- 
men from the cavity of a large Salpa, and they 
may, therefore, be said to be parasitic on mollusca 
as well as on Acalepha, In its free and inde- 
pendent state, when observed in a vessel of, sea- 
water, Phronima atlantica is perfectly transparent, 
and the slender arms and tumid hands are covered 
with red-brown dots. In its habits it is somewhat 
peculiai’, even for a shrimp. Suspended head down- 
wards in the water, it remains motionless like a 
spider in its web, the long hind legs extended with 
the tai-sal joints all bent back, the prehensile 
arms, with their gibbose spotted hands, arched 
inwards, and the tail curved forward towards the 
