is 9 6. NOTES AND COMMENTS. 151 



insisted, the important aid it lends to geologists. Some remarks by 

 Mr. Clement Reid, which are here published, are sufficient evidence 

 of this. " One is again struck," says Mr. Reid, " by the common 

 occurrence of loose angular stones at places and depths apparently 

 well beyond the reach of any bottom drift — at least beyond the reach 

 of currents likely to move such coarse material. This stony sea-bed 

 is in all probability the result of submarine erosion of glacial deposits. 

 Its occurrence renders comparison between recent marine deposits of 

 these latitudes and Tertiary deposits a task of peculiar difficulty ; for 

 not only is the nature of the true marine sediments masked, but the 

 fauna also must be greatly altered. It is evident that numerous 

 species which need a firm base on which to affix 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 Cellavia fistulosa (found to the south-east of the Calf Sound, 

 twenty fathoms). They are in many respects strikingly like certain 

 parts of the Coralline Crag." 



The Attachment of Larvae. 



Another line of investigation started by the Liverpool Com- 

 mittee during 1895, is inquiry into the times and modes of attachment 

 of the larvae of various species, and also as to the most suitable 

 substances for particular kinds of larvae to settle down upon. This 

 has been carried out by 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. " So far, glass seemed in the early 

 spring (February and March) to be the favourite substance. A sur- 

 prisingly large number of algas, compared with the animals, appeared, 

 and nearly all were on the glass slips. Later on, in the summer, 

 barnacles (Balanus) made their appearance in great numbers on the 

 slips of wood and on the wooden buoy at the top of the apparatus, 

 while all the upper part of the rope within a few feet of the surface 

 became covered with algae. A number of ascidians (Ascidiella virginca) 

 were also found, in August, to have attached themselves to the rope, 

 and seemed to have got as far as possible in between the strands and 

 into the coils of the knots. On the upper pieces of slate, and, in one 

 instance, on a piece of glass, there were young specimens of the 

 tubicolous Annelid, Pomatoceros triquetev, in no case more than a h to 



