20 ORCHESTIIDjE. 



third from the apex. The structure of the hair towards 



the point is obscurely spiral. Those 



upon the tail are often considerably 



worn down by the friction induced 



by leaping. The central tail-piece is 



represented in this species by two 



small calcareous nodules. * The 



surface of the body is highly polished. An examina- 

 tion of the structure of the integument by the aid of the 

 microscope shows traces of the original cell-character of 

 the tissue and the granular arrangement of the salts within 

 the cells. There are, moreover, certain larger markings 

 that assume somewhat the form of the letter T. But we 

 are not able to recognize them as associated with any 

 peculiar function. 



The female exhibits the character of the species 

 less strikingly than the male, being considerably smaller, 

 and having the antennae shorter. So great indeed 

 is the difference, that Leach, in the " Edinburgh Ency- 

 clopaedia," inserted it as a distinct species, under the 

 name of Talitrus littoralis, an opinion which he afterwards 

 corrected in the " Linn 0e an Transactions," vol. xi. 



The Sand-hoppers dwell near the margin of the sea, 

 where the highest spring-tides rise. They are never 

 found in the water, but dwell beneath the decaying sea- 

 weed, or other stray substances which preclude the eva- 

 poration of moisture from the scorched sandy beach. Mr. 

 Gosse tells us that he has found them at the depth of 

 several inches in half-rotten beds of algae, where the fer- 



* Our figures in page 16 were taken from very large males, captured at 

 Weymouth, by Professor Bell. In these individuals the central tail-piece is 

 heart-shaped and spined (fig. z\ and the upper antennae extend to the tip of 

 the penultimate joint of the peduncle of the lower, of which latter the rela- 

 tive proportions of the joints were carefully measured for delineation. (W.) 



