ni;\ciivrKi. 171 



very pale ; and five or six weeks after coming into my possession, it was 



delineated white, mi November :I. Plate XXX IX. fig. 1. 



Such specimens arc nuv. I have never seen any, unless of small 

 dimensions. However, they M i r \ i vo aa readily aa others, and possibly 

 live as lonir ; but whether attaining lull size, without the wanted modi- 

 licit iun .f colour, is doubtful. No one informs me of having seen a large 

 Common Crab trhitr. The a-pect of such specimens, in their earlier 

 stage, is different from that of the ordinary appearance, as may be Been 

 from liir. '.'. \vhicli is introduced IHTO for (lie purpose of contrast. 



The specimen, fig. 1, ha 1 I urn taken on the 29th of September ; it 

 mutilated its companion on the 20th of October, without any symptom 

 of itself having suffered. Rejecting food on the 8th of November, it 

 cast its hhell on the !>th ; when the new animal came in, larger than be- 

 fore, and still paler. Ix-ing now almost white, fig. 2. Its next exuviation 

 was on April :idth, when the new shell coming in again somewhat larger, 

 was still pure white, of soft ami delicate aspect. Jig. 3. 



It is surprising to behold a creature of ample size, with which we 

 are familiar, presented in miniature among many of its kind of darker 

 hue, but by exception clear and polished, and white as the drifted snow. 

 The difference at first sight is unaccountable, so great and irreconcileable, 

 that the spectator will pause in allowing their kindred. 



The shell now subsisted from April 30, until September 12, when 

 exuviation produced another considerably larger than previously, of the 

 purest white, so clear and tranf<parent, that the place of the intcranea, 

 or the organs confined within, shone through its refined substance. The 

 old one remained quite entire, that is without gaping, or any evident 

 separation of the line of union between the hind pair of limbs, whence 

 the ne\\ shell had issued. All the different parts besides remained aa 

 usual in their own proper position. Delineation of this subject wa 

 postponed until Xovemlier 10, or about two months ; whereon it may 

 be remarked, th.it although no sensible enlargement of the animal en- 

 sues, some slight 'natural or accidental alteration is usually perceptible. 

 It is generally of trilling importance. Fiir. 4. 



In regard to colour, I : the preceding facto aa satisfactory 



