Pontophilus bispinbsus. 271 



cabinet, with all their defections. I shall be glad if Mr. 

 Westwood can refer me to any description of them. I also 

 send, for his inspection, a drawing of a species of (I conceive) 

 Anceus, a genus new to our shores ; but whether it be the 

 forficularius of Risso, or not, I have no means of determining. 

 Four of them I found along with the other two animals. 



You mention the changes which Crustacea undergo as 

 they advance in age. I have some specimens illustrative of 

 this, and may probably trouble you with a communication 

 upon the subject, when my observations are more matured. 

 If you can suggest any point in the natural history of the 

 Crustacea which requires elucidation, I shall be happy to 

 direct my attention to the subject, and give you the results. — 

 S. Hailstone, jun. 2. Denmark Place, Hastings. [Received 

 March 11. 1835.] 



Ord. Macroura, Fam. Palaemomcks, Gen. Pontophilus [Sp. bispinosus 

 Westwood, in p. 273-X/g. 30.)] 



Pedipalpes (a) with the last joint rather longer than the 

 preceding one, and bluntish at its termination. — First pair of 

 legs (c) compressed, didactyle, with the thumb very short; 

 second pair [b) rather shorter than the first, didactyle, the 

 last joint half the length of the preceding one, which is com- 

 pressed ; third pair very slender, as long as the first pair, 

 with a simple claw; fourth pair (d) and fifth pair of equal 

 length, rather longer than the third, and somewhat thicker, 

 but slender : claws simple. — Thorax with two prominent dorsal 

 spines, one considerably behind the other, and on each side a 

 row of blunt notches. A spine at the outer edge of the external 

 plates of the tail. — Colour yellowish mottled with brown. 



If this be a species of Pontophilus (with Leach's descrip- 

 tion of which genus it tallies in all respects except the com- 



T 4 



