in certain Crustaceous Animals. 551 



I have found all the characters, as well as the individual form, 

 perfect; and in specimens of the Portumnus variegatus and 

 Pirimela dentata, each a line in length, I have made the same 

 remark. 



While upon the changes in form of the Crustacea, I may as 

 well mention a few other observations which may be interest- 

 ing. Of the Macroura I have seen a specimen of the Galatea 

 squamifera, of two lines in length, with all the spines and 

 features observable in the full-grown ones ; the difference being 

 in their unfinished form, the marginal spines being more like 

 expansions of the lamellae forming the carapace. 



A specimen of the Pisa GibbszV, not quite two lines in 

 length, differed from the old ones in nothing but the obtuse- 

 ness of its dorsal spines. A specimen of the Macropodia 

 Phalangium of the same size has a rostrum of a length pro- 

 portional to its size, which is a fact bearing upon the question 

 of the doubtful Macropodia I have communicated to you 

 [p. 263, 264. 267, 268.]. The following observation is of a 

 case analogous to that of the spinous arms of the young 

 Porcellana Linnedna [p. 265. 268, 269. 394, 395. 552.]. Some 

 specimens of the males of the Corystes Cassivelaunus have 

 their fore legs about 2 in. long, which in others are at least 

 3 in. Now, upon those of the former, on the inner side of the 

 arm and wrist, are two sharp hooked spines, which in the 

 latter degenerate into blunt tubercles ; the alteration being the 

 result of age. 



Of the forms of crabs, in the earliest stages of developement 

 from the ova, I have had no means of judging; but, as far 

 as my observation extends, they seem, in comparison with the 

 size which they afterwards attain, to assume their final shape 

 when very small, and, consequently, at an early period of 

 their existence. 



Cheltenham, August 22. 1825. 



The Species of Crustaceous Animals discovered and de- 

 scribed by Mr. Hailstone, and illustrated and annotated on by 

 Mr. Westwood. (261 — 276. 394, 395.) — After your own 

 observations [p. 395.] in reply to Mr. Hailstone [p. 394, 

 395.], in which I fully concur, I know not whether it be 

 necessary for me to offer any further remark ; but, lest my 

 silence should be deemed evidence of the justice of Mr. 

 Hailstone's animadversions, I may be allowed to observe, 

 in the first place, that I can see no great impropriety in 

 suggesting (as I merely did) the name of minuta [p. 267.] for 

 a small animal, or that of rubra [p. 274, 275.] for a red one. 



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