64 ADDENDA TO 



iinlooked for a fact, and after numerous fruitless attempts 

 year after year, he at length procured, in 1827, examples 

 of the common Crab with spawn apparently ready to 

 hatch, and by means of the kind assistance of Mr.Kingdom, 

 Naval Storekeeper at Hawlboline, succeeded in protecting 

 one individual until the young burst from their envelopes 

 and swam about in myriads, under the exact form given 

 in the plate ; in this stage, they are colourless and 

 transparent as glass, except the dark central part of each 

 eye, and a blackish dot on each side every abdominal 

 segment, the dorsal spine exhibiting a pale pink tint for 

 nearly half its length from the point downAvards. 



Some gentlemen having expressed doubts as to the imi- 

 versality of the metamorphosis in the Decapoda, let it be 

 remembered, that the contrary opinion hitherto held, is 

 merely an assumption, and that the metamorphosis having 

 been proved in a single instance, amongst animals so 

 uniform in structure as the Homobranchia, we may safely 

 infer from analogy, as far as regards the particular tribe 

 alluded to, that it is general ; we have seen that in 

 the common Crab, (Cancer pagurus) the young is a Zoe, 

 an animal so totally different in its aspect, structure, and 

 habitudes, that it is evident, a very remarkable metamor- 

 phosis must take place before it can assume the form so 

 familiarly known of the parent animal ; when this fact is 

 coupled with the circumstance, of no less than six other 

 Zoes having been figured, (see Pi. I.) which from their 

 localities and difference in form, most probably belong to 

 as many genera of the Decapoda, it can hardly be said 

 that the universality of the change wants confirmation. 

 Besides, since the former JVIemoir was penned, the Author 

 has had a confirmation of it in one of the West Indian land- 

 crabs, and in some other of our most widely separated 

 native genera, authorizing what he has advanced at p. 2, 

 viz. " that the greater number of the Crustacea do 

 actually undergo transformations, of which, in addition to 



