PRESIDENTIAL ADDRESS. 13 



One of the facts which attracted my attention when I first 

 begun to study deep sea mollusks was the singularly small 

 number which showed signs of having been drilled or attacked 

 by other mollusks. Apart from those showing the marks of fish 

 teeth or the dental machinery of echinoderms, it is extremely 

 rare to find drilled bivalves or univalves such as make up the 

 great mass of the jetsam on even- sandy beach. Such cases 

 occur, but the occurrence is always exceptional and the holes 

 which are most often found in abyssal shells are those which are 

 due either to the friction of seme hermit crab or to the ero- 

 sive properties of the secretions of certain annelids which 

 fix their irregular tubes upon the outer surface of the shell. 

 These injuries cannot easily be confounded with the circular 

 drill holes of carnivorous gastropods. 



Having handled more deep sea mollusks than any other 

 naturalist now living, and spent, probably, more time over 

 material procured by the dredge from shallow water, than any- 

 one else of my acquaintance, I do not feel that I am presump- 

 tions in affirming the remarkable difference which obtains in 

 this respect between the dead material from the L-itoral and 

 from the extra-Litoral regions, respectively. 



This brings me to a conclusion which I have elsewhere pub- 

 lished with less detail. The animals belonging to the mollusca 

 which are found in the Archibenthal and Abyssal regions, 

 especially the latter, do not live in a perpetual state of conflict 

 with one another. A certain amount of contention and 

 destruction doubtless goes on, but on the whole the struggle 

 for existence is against the peculiarities of the environment 

 and not between the individual mollusks of the area concerned. 

 It is an industrial community, feeding, propagating and dying 

 in the persons of its members and not a scene of carnage 

 where the strong preys upon, his molluscan brother who may 



