Crustacea. 7279 



themselves to my mind which militated strongly against the presumption of its b^ing 

 a native of the tropics, first, because tropical aquatic plants are only received at Kew 

 in a dry state, and 1 question whetlier a mollusk so decidedly aquatic as the Pliysa 

 could in any stage of its existence retain its vitality, and survive the lengthened period 

 occupied in the transmission of the plants to this country ; and secondly, assuming 

 that it did so survive, could anything tropical having life retain its vitality after being 

 exposed alfresco to the inclemency of a long and severe winter like the last ? Being 

 satisfied, therefore, that it was not an exotic species, and that its native habitat was not 

 within the tropics, 1 continued my investigation, and at length I obtained a clew 

 which brought to my recollection that nearly twenty years ago I collected some aquatic 

 plants in a certain locality in the vicinity of the metropolis, for the use of the Royal 

 Botanic Garden at Kew ; and as I have just discovered that the Physa is found in that 

 locality, as well as in Kew Gardens, the inference is obvious that it must have been 

 introduced to the Royal Gardens with the aquatic plants in question, where it 

 must have remained ever since. But I am constrained to refrain from mentioning 

 this locality at present, from the fear that if known the Physa might become extinct 

 there, owing to the rapacity of collectors in collecting specimens. — A. Choides ; Royal 

 Gardens, Kew, October 20, 1860. 



On the Habits of Phronima atlantica. — Although it is perfectly true of the large- 

 headed transparent shrimps comprising the family Phronomidae, that they are more or 

 less parasitic, being found stowed away in the pouches and other cavities of the equally 

 pellucid Acalephse, yet sometimes they swim freely about and are frequently taken in 

 the towing-uet. I have taken a specimen from the cavity of a large Salpa, so they 

 may 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 legs and tumid chelae of the fifth pair are covered with 

 Md-brown dots. In its habits it is somewhat peculiar, even for a shrimp. Suspended 

 head downwards in the water, it remains motionless like a spider in its web ; the long 

 hind legs extended with the tarsal joints all bent back ; the prehensile fifth pair, with 

 its gibbose spotted hand, arched inwards, and the post-abdomen curved forwards to- 

 wards the head. In this attitude of attention he remains eagerly on the watch, and 

 while staring with its great eyes, separating its jaws, and keeping ready its man- 

 dibles, the false feet of the abdomen are incessant at work producing a current 

 towards the mouth. No sooner is some minute organic particle drawn within the in- 

 fluence of the vortex than the head and tail of the Phronima are brought together, 

 and the object is immediately seized, if large enough, by the thumb and finger of the 

 freckled hands, conveyed to the mouth and greedily devoured. When placed 

 in spirits the skin becomes opaque, the colour of the legs is changed into a pale yel- 

 low and the red-brown spots disappear. When we compare the delicate oceanic 

 organisms seen fresh from the deep sea with the specimens in our bottles, well may 

 we mournfully exclaim with St. Pierre, " Our Books are but the Romance of Nature 

 and our Museums her Tombs.''— Arthur Adams. 



