PAEKE ON DREDGING ON THE DOGGER BANK. Q27 



with Hydractinia echlnata, Linne, — and odd valves of Cyprina Islaiidlca 

 occurred abundantly, though with tho exception of DcntaUiim entails, 

 which seemed to he generally distributed on all sides, living forms were 

 seldom met with at the same time. This seems strange, and would 

 suggest the idea of a " struggle for existence." Mr. Jeffreys in his dredg- 

 ing report read before the British Association (1863) says, " Considering 

 the vast extent of sea-bottom which has never been touched by the dredge, 

 the exceedingly limited space measured in square acres which can be 

 explored by means of it, and the infinite variety of ground comprised 

 within any given area, I would suggest that great caution should be used, 

 and further inquiries made before the common expression is hazarded 

 that certain species are now " dying out," whether slowly, gradually, or 

 rapidly. I do not believe that such is the case. The fact of finding only 

 dead shells in a particular spot is no proof that living ones connot be met 

 with in the same district. There may be, and often is, an accumulation 

 of dead shells in one place, like bones in a grave-yard, in consequence of 

 the shell-fish having deserted it for some reason with which we are not 

 acquainted, while the living brood migrates or shifts its quarters. The 

 proportion of dead to living specimens, even of common species which 

 are not supposed to be "dying out," is often remarkable. Among 

 many hundred single valves of Lima subauriculata, which were this year 

 dredged in Shetland, there was only one live specimen." I may mention 

 a similar occurrence in my dredgings on the Manx Coast ; in 1862, fine 

 living examples of Lwia Loscombii were brought up, in fifteen fathoms 

 water, off Douglas Head, and in the same locaUty Pectunculus glycymeris 

 occurred in great numbers. In July, 1863, I dredged both species in 

 abundance, but, with the exception of three small ones of the latter, all 

 the specimens were dead, and in most cases detached mutilated valves. 



Ten or twelve specimens of Solen pellucidus, Pennant, were brought 

 up in 45 fathoms water, but more or less injured by coming in contact with 

 the debris ; also a young living example of Buccinopsis Dalci, J. Sowerby. 



The following list will show the specimens taken : — 



MOLLUSCA. 



