CRUSTACEA. 475 



Its geograpliical range is from the Orkneys, where it reaches • 

 its largest size, to the Mediterranean. On our coast it ranges 

 from the shore to about three fathoms of water, and is very 

 common. 

 PoKCELLANA LONGicoRNis. — Pennant, pi. \,fig. 2. 



Pisidia longicornis. — Leach, Bid. des. set. nat., xviii, p. 54 (not 

 Malae. Brit.); Milne Edwards, Hist des Crust., Vol. 2, p. 257 ; Bell, 

 Stalk- Eyed Crust, p. 193. 



Porcellana Leachii. — Gray, Zool. Miscel., p 15 ; Couch, Cornish 

 Fauna, p. 1Q. 



Common on zoophytic and rocky ground, from one to forty 

 fathoms of water. It seldom frequents the shore above half -tide. 



I think that there can be little doubt but that Mr. Bell is 

 correct in his opinion that Porcellana acanthecheles of Couch's 

 previous Cornish Fauna is but a young specimen of this species. 



GALATSIABM. 



GrENTTS, G-ALATHEA. — Fair. 



'* Carapace covered with transverse sections edged with short 

 hair ; snout (rostrum) advanced and spirey ; half of the abdomen 

 (pleon) permanently bent under." 



Carapace depressed ; anterior pair of legs chelate, equal, flat, 

 long ; posterior pair feeble, unfit for walking ; abdomen (pleon) 

 broad, flat ; posterior pair of pleopoda (tail) broad, flat ; telson 

 wide. 

 Gaiathea strigosa (Plated Lobster) ; Linn. 



G". spinigera. — Leach, Malac, pi. 28 ; Pennant, pi. 14, p. 26 

 Milne Edwards, Hist, des Crust., t. 2, p. 323 ; Bell, Stalk-Eyed 

 Crust., p. 200. 



"Common, and in its younger state not easily distinguished from 

 G. squamosa. It is incapable of any motion but backward, and 

 rarely rises above the bottom, when by a laborious motion of its 

 tail it continues to retreat from its enemies ; and its usual pro- 

 gress is creeping, and by its legs only." 



Mr. Couch's observations must have been on the sea-shore 

 when the animal is out of the water. In the sea, Galathea as 

 well as Porcellana, having the power of swimming very rapidly, 

 and this they do mostly with the power of the whole tail (or 

 pleon.) 



