262 
PEOGRESS OF MICROSCOPICAL SCIENCE. 
Through Dr. Carpenter he received from Mr. Power an offer of a 
considerable number of larvae of exotic species, together with the 
parents from which they had been obtained ; in relation to which 
Mr. Power wrote : 
" Dear Sir, — I have to thank you for your kindness in answering 
my letter to Dr. Carpenter, and for the memoirs. 
" My collection of Crustacea and the microscope slides of the 
larvae are at present, and have been, packed up in Fort Louis. Now 
I am again on detachment ; and if left here in peace for a few months, 
I shall arrange my specimens and finish up the microscopic drawings. 
" All my larvae are hatched in basins (the only kind of aquaria 
my nomad life allows me to use), so each crab or prawn, &c., whose 
larv£e I possess is identified with its young ; and this reminds me that 
on reading Fritz Miiller's paper in the ' Annals ' * I was much 
astonished, as none of the prawns or prawn-allies whose young I have 
hatched show any such Naupliiis form as shown in figures 1 and 3, 
&c. ; but all I have observed as yet are born like fig. 8, or near it. 
" I have been quite unable to rear any crab-larvae beyond a day or 
two after birth ; whether they require moving water or not I do not 
know ; but certainly, though I have kept the parents alive for several 
weeks in basins (the water changed once or twice in twenty-four hours) 
of salt water, the same method would not succeed with the larvae. I 
then tried small aquaria, and signally failed again. 
"I have not been in the neighbourhood of fresh water as yet, so 
have had no opportunities of observing the fresh-water Crustacea, 
though there are a good many crab and shrimp forms. I have found 
two kinds of that curious parasitic crustacean which adheres like a 
little polypus, a mere bag with a peduncle, but containing hundreds 
of young Crustacea whose genus I do not know, as I cannot find any 
account of them in Van der Hoeven's ' Zoology.' | 
" If I succeed in getting posted to one of the regiments here, my 
life will be more stationary, and I shall have far better chances of 
working my crab-hatchings. 
" In Fritz Miiller's paper before referred to, I fancy that he has 
not hatched the different larvae mentioned. After reading the paper 
very carefully, I could not help fancying that the various stages of 
development were not hatched through, but specimens were captured 
at different times, and perhaps larvae of totally different species have 
been given as stages of the same animal. I say this with great doubt ; 
but reading the paper will, I think, bring everyone to the same con- 
clusion. Thus he says, ' the unaltered Naujplius form, probably the 
same in which the animal escapes from the egg, came under notice 
only once;' again, 'This larva (taken on the 13th of January) is 
closely approached by four others, probably belonging to the same 
swarm, which were taken at the same time (24th January) ; ' and 
so on. 
" To tow a net in these tropical seas and to examine all the micro- 
* 1864, vol. xiv. p. 104. 
t [New genus allied to Saccullna, which hatch larvae in the cirriped pupa 
stage.— C. S. B.] 
