ON TIIK MARINE ZOOLOGY OF THE IRISH SEA. 465 



greatly altcrod. It is evident that numerous species which need a firm 

 base on whicli to attix themselves will be encouraged by a stony bottom ; 

 while in a Tertiary deposit, formed under identical conditions, except for 

 the absence of stones, they may be entirely missing, having nothing but 

 dead shells to which to attach themselves. 



' Notwithstanding this peculiarity of most of the dredgings, a few 

 samples may well be compared with our Older Pliocene (Coralline Crag). 

 I would particularly draw attention to certain localities where material 

 almost entirely of organic origin has been obtained. Of these perhaps the 

 most interesting are some samples full of Cellaria Jistulosa (found to the 

 south-east of the Calf Sound, 20 fathoms). They are in many respects 

 strikingly like certain paints of the Coralline Crag. The more ordinary 

 type of Coralline Crag, with its extremely varied polyzoon fauna, we 

 cannot yet match in British seas : it was probably formed, as the moUusca 

 indicate, in a sea several degrees warmer than ours. 



' It wag hoped that in the course of these dredgings some light might 

 be thrown on the Tertiary strata underlying the bed of the Irish Sea, for 

 in the North Sea the dredge occasionally brings up hauls of Tertiary 

 fossils. This expectation has not yet been realised.; but possibly, by 

 dredging in the channels where the submarine scour is greatest, such 

 deposits may yet be reached. It is very important to obtain some know- 

 ledge of the Tertiary bed of the Irish Sea, for Irish Pleistocene deposits 

 contain a considerable admixture of extinct forms, which may be derived 

 from Tertiary deposits below the sea-level. The Glacial Drift of Aber- 

 ileenshire contains Pliocene Volutes and Astartes, derived from some 

 submarine deposit off the Aberdeenshire coast. The so-called " Middle 

 Glacial Sands " of Norfolk ai'e full of shells which I now believe to be 

 ilerived from some older deposit, probably beneath the sea.' 



The imjiortant influence of the shore rocks upon the littoral fauna has 

 not been neglected, and lists and observations are accumulating, but that 

 subject is left over for a fuller discussion in the final report next year. 



OTHER INVESTIGATIONS. 



Several new lines of investigation have been started during the yeal', 

 and are still in progress. One of these may be called the ' larval-attacli- 

 ment inquiry,' and consists in sinking in various parts of the bay an 

 apparatus composed of a rope weighted at one end and buoyed at the 

 other, and having a number of slips of glass, slate, wood, etc., attached at 

 equal distances along its length. These ropes are hauled up and examined 

 periodically, and may be exjiected when further observations have been 

 taken to give information as to the times and modes of attachment of the 

 larvse of various species, and also as to the most suitable substances for 

 particular kinds of larvje to settle down upon. So far glass seems the 

 favourite substance, and a surprisingly large number of algae compared 

 with the animals have appeared. 



' Drift Bottles ' a\d Surface Currents. 



In connection with the investigation of the surface life, in discussing 

 the appearance and disappearance of swarms of certain Copepoda and 

 Medusae, and in considering the possible influence of the movements of 

 such food matters upon tiie migrations of fishes, and also in connection 

 with the movements of the fish ova and floating embryos, it occurred to 

 1895. II II 



