SULCATOR. 175 



in their capability as members of perambulation, obtain, 

 through the great expanse of surface which each joint dis- 

 plays, a paddle-like power, by which they are enabled to 

 progress through the sand without resorting to leaps and 

 bounds, the usual mode of passage among the Talitri, or by 

 crawling whilst lying upon the side, after the manner of 

 Gammarus and other Amphipoda. 



Sulcator marinus, Spence Bate. — Basis of three hind 

 legs not developed in the form of scales. 



Banff (Mr. Edwards) ; Macduff (Mr. Gregor). 



Mr. Spence Bate, in writing on the habits of Sulcator 

 arenarius,* remarks that naturalists suppose the respiratory 

 process to be carried on in Amphipoda " by a current ex- 

 cited through the agency of the natatory feet, passing con- 

 tinually over the branchiae situated beneath the thorax ; but 

 the peculiar habits of this animal, living as it does chiefly 

 beneath the sand, must materially interfere with the passage 

 of such a current. Then may we not presume that the 

 great extent of dermal surface, which is prolonged by large 

 hair-like processes, may offer a medium through which the 

 blood may be aerated, and so lessen the dependence of vital 

 action upon the waters circulating freely over the branchial 

 * Ann. and Mag., 2nd series, vol. vii. p. 319. 



