14 HYPERIID^E. 



We believe that Professor Milne Edwards was the first 

 to point out the great difference of form existing between 

 the young and the adult in this division of Amphipoda ; 

 but Mr. Gosse, in his pleasant " Naturalist's Rambles in 

 Devonshire," has figured the young of this species. We 

 also have had an opportunity of examining them, a 

 drawing from which is given at figure -u * at the head of 

 this description. The head of the young animal is 

 small, and the eyes, consequently, are not much deve- 

 loped. The body is very large, while the tail is narrow 

 and straight, and lies compressed beneath the body. Mr. 

 Gosse has figured all the legs, but in our specimen two 

 pairs appeared to be wanting. This may be accounted 

 for by the circumstance that Mr. Gosse's specimens were 

 older than ours, he having procured his as free and inde- 

 pendent creatures, whereas ours were procured direct 

 from the incubatory pouch. In the caudal appendages 

 there also appears to be a difference in the degree of 

 development as observed by Mr. Gosse and ourselves, 

 arising, no doubt, from the above-named cause. 



This species, which must be considered as the type of 

 the genus, was first taken by Col. Montagu on the 

 southern coast of Devonshire, and it has been sent to us 

 from Jersey by Mr. George Parker. Specimens from a 

 Ehizostoma at Lamboy in Ireland have been communi- 

 cated to us in Mr. W. Thompson's collection, belonging 

 to the Belfast Museum, and a number of specimens stated 

 to have been also captured in the stomach of a Medusa, 

 and given to us by the late lamented Rev. Professor 

 Henslow. Mr. White records it as inhabiting the pouches 

 of Rhizostoma Cuvieri on the Dublin coast upon the autho- 

 rity of Mr. Hyndman. Mr. Edward has sent it to us from 



* This mark is intended to symbolize the young animal. 



