Mr. C. Collingwood on Nudibranchiate Mollusca. 465 



animal is one of the most common and widely distributed Nudi- 

 branchs of the Mersey. It occurs more or less in all the locali- 

 ties frequented by the zoologist both upon the Lancashire and 

 Cheshire shores, but is in the greatest profusion in the hottest 

 part of the summer. The spot where I have found it in the 

 greatest numbers is a remarkable one, and worth recording. The 

 old landing-stage from which the ferry steamers run, is a pon- 

 derous barge-like structure supported upon iron pontoons, which 

 are capable of being withdrawn individually. On the land side 

 of these pontoons, and in the crevices between them, vast quan- 

 tities of Tubulmia indivisa and mussels accumulate and flourish, 

 so that from time to time it is necessary to withdraw the pon- 

 toons one by one and scrape them with iron scoops, in order to 

 rid them of the masses which choke them up. This Tubularia 

 affords food and harbour to a vast number of animals, including 

 several species of Nudibranchs; and among them Dendronotus 

 arborescens is conspicuous. In company with my indefatigable 

 friend Dr. Edwards, on a fine day in the month of August last, 

 we gathered specimens of Dendronotus from this spot as fast as 

 we might pick blackberries from a hedge ; so that in a quarter of 

 an hour we found ourselves possessed of upwards of forty fine full- 

 sized specimens. It is not, however, at all times of the year that 

 they are to be found in this profusion. On the 9th of February 

 last I visited the same spot, and found Tubularia indeed in 

 the most magnificent condition, with pendent clusters of ovi- 

 form gemmules an inch long ; but though I searched long and 

 diligently, no trace of Dendronotus could I find. Indeed, the 

 first specimen of the season made its appearance, on the verge of 

 low-water at Egremont, on the 5th of the present month. This 

 species is very sluggish in its movements, and will not live more 

 than a day or two after its capture. Whether it requires a constant 

 supply of the heads of Tubularia for its sustenance, or a constant 

 renewal of sea -water for its respiration, I am not aware; perhaps 

 both. We have pale-yellow as well as rich-brown varieties. 



Doto coronata. — This is the only species of Doto hitherto met 

 with in the Mersey, but is very common and widely distributed. 

 Along the Cheshire shore of the estuary it is in great abundance, 

 especially at Egremont and New Brighton, where it may be 

 found upon the under side of stones (the larger the better) all 

 the year round, as well as upon fronds of Laomedea ffelatinosa, 

 which is our commonest zoophyte. I have counted a score upon 

 a single large stone. On the Liverpool side it may be found 

 upon the Tubularia of the landing-stage. I have never found 

 one, however, half an inch long, — the average size being a quarter 

 of an inch, and the largest three-eighths. They are very vari- 

 ously coloured, seldom pale, and sometimes very richly marked, 



Ann. ^ Mag. N, Hist. Ser. 3. VoL iii. 30 



