On the Development of the Crustacean Embryo. 175 



the parents from which they had been obtained ; in relation to 

 which Mr. Power wrote : — 



" Deak 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 micro- 

 scopic drawings. 



" All my larvjB are hatched in basins (the only kind of aquaria 

 my nomad life allows me to use) ; so each crab or prawn &c. whose 

 larvae I possess is identified with its young. And this reminds me 

 that on reading Fritz Miiller's paper in the ' Annals ' (1864, vol. 

 xiv. p. 104), I was much astonished, as none of the prawns or 

 prawn-allies whose young I have hatched show any such Nauplms 

 form as shown in figures 1 & 3, &c,, but all I have observed as 

 yet are born like fig. H, or near it. 



" 1 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 24 

 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 freshwater 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 1 

 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 i-eading 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 diffe- 

 rent species have been given as stages of the same animal. I say 

 this with great doubt ; but reading the paper will, I think, bring 

 every one to the same conclusion. Thus he says, ' the unaltered 

 Nauplius 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 

 microscopic Crustacea would give a most extraordinary assemblage 



[* New genus allied to Sacculina, which hatch larvae in the cirriped pupa 

 stage.— C. S. B.] 



