84 
A COENISH FAUNA. 
Its peculiar form, and the failure up to the present time, of 
teacmg ae animal through aU its stages of development, makes 
it an object of interest ; and I think it worthy of consideration, 
particularly by those who, as a crucial test in the theory of 
evolution, demand the exposition of a series of suceessional 
forms of life. They should remember that of this animal so com- 
mon on our coast and in our markets, that there is no one yet who 
has been able to determine the several forms through which this 
animal passes in its growth from the zoea to the adult stage, 
its first form is that known as Phjllosoma, its next stage is, I 
believe, that known as the genus AmpUon, but this is only con- 
jecture, as it has not been traced or clearly determined beyond 
the form the young quits the ovum. How, therefore, if a common 
form like this Crawfish cannot be traced from one end of its life 
to another, can we expect that the record of many forms of lost 
animals can be made perfect ? 
The young quit the ovum mostly at the same time, and Mr. A. 
Uoyd tells me that in the aquarium they suspend in the water 
tor a day or so like a monster cone-like cloud, after which they 
disperse and die. 
ISALA&INIBJE. 
Genus, Oaxlianassa. — Leach. 
“ The integuments, except of the claw, less, soft ; caudal plates 
lai^e and fobaceous ; first pair of legs didactyle, unequal; second 
pair small, didactyle third pair not didactyle. Carapace with 
rostrum. 
Callianassa subteeeanea.— Burrowing Shrimp —Leach, Malac. 
Brit. t. xxxii ; Milm LJdwards, Hut. des Crust., vol. ii, p. ,3 and 9- 
Montague first took this species, probably, in Kingsbridge river; 
I took it many years since in company with the late Professor 
Kmahan, in Plymouth Sound. Mr. Couch makes no remark 
about it, or says where it was taken, but most probably off 
Polporro, but as it is a bui-rower it probably escapes observation. 
Genus, Axius. — Leach. 
“ Integuments moderately firm ; caudal plates large and foli- 
aeoous. Pir.st pair of legs chelate, unequal ; second pair chelate, 
subequa.1 ; the following pairs not didactyle. Carapace with a 
small triangular rostrum.” 
