inhabiting the Estuary of the Dee. 197 



pany with E. concinna and E. despecta : this is E, exigua, which 

 inhabits the same fronds of Laomedea gelatinosa as the other 

 two, being found in rock-pools considerably above low-water 

 mark; but it appears to be much less numerous than E. de- 

 specta. There are thus four species existing in the Mersey 

 which have not hitherto been met with in the Dee ; and it will 

 presently appear that the Dee possesses five species which have 

 not yet made their appearance in the Mersey. The Polycera 

 Lessonii, recorded as dredged off the Mersey, was taken about 

 midway between the two estuaries, and can hardly be claimed, 

 therefore, as the especial property of either. 



Among those species common to both estuaries, one, however, 

 deserves especial mention, viz. Doris proxima, from the fact that 

 although found both in the Mersey and Dee, I am not aware of 

 its having been taken anywhere else. In external characters it 

 closely resembles D. aspera \ but it is not a little remarkable 

 that D, aspera has not yet been detected on these shores. I 

 have searched in vain for it myself, nor can I hear that any one 

 else has taken it *. It appears to be replaced by its ally D. 

 proxima. This fact would lead one to suppose it to be a mere 

 local variety, were it not that the tongue differs so widely in the 

 two species that Mr. Alder remarks, " some naturalists might be 

 disposed to consider them generically distinct." 



I had the satisfaction of adding to the local list, in the autumn 

 of 1859, Eolis rufibranchialis, characterized as one of the most 

 slender and delicate forms of the genus. This beautiful species 

 I first met with in July, at Hilbre Island, in the Dee, where it 

 was of large size, and in some numbers. Visiting the Egremont 

 shore of the Mersey in March of the present year, I was sur- 

 prised to find as many as two dozen specimens of this brilliant 

 creature where I had never seen it before. They were very 

 brightly coloured, but not so large as the examples taken in 

 the Dee. 



The hunting-ground for these little animals in the estuary of 

 the Dee is of very limited extent. On the Cheshire side, long 

 before the time of low water, the tide runs out, leaving a vast 

 and bare expanse of sand, most unproductive of animal life. 

 The river is six miles wide at its mouth ; and with the Welsh 

 side I am unacquainted, owing to its distance and inaccessibility. 

 But about a mile and a half from Hoylake, at the north-west 

 angle of the Cheshire shore, commences a ridge of New Red 

 Sandstone, nearly parallel with the coast, extending up the river 



* In a note now before me, from Mr. Price, he says, " Every Doris 

 (aspera) I ever suspected and sent to Mr. Alder, he pronounced to be D. 

 proxima. They were sometimes pure white ; their spawn dull yellow and 

 inconspicuous, forming a squarish spiral." 



