in the Deptlis of the Sea. 433 



rarely, and as it were accidentally, cauglit on our coasts, and 

 whose yet unknown dwelling-place may probably be the 

 greatest depths, such as Lampris guttatus^ Briinnich, Trachy- 

 pterus arcticusj Nilsson, Gymnetrus Grillu\ Lindroth, &c. 



There is now, therefore, quite a considerable and unexpected 

 multitude of forms which live in what a short time ago were 

 considered uninhabited depths ; but there are certainly still 

 many more which are as yet unknown. It seems to me, there- 

 fore, stiH too early to draw from the facts we have discovered 

 more than some general results which seem as it were to pre- 

 sent themselves to our notice or are forced upon us as scientific 

 conclusions. 



Of the great divisions of the animal kingdom we find at 

 these depths the mollusks to be the most numerously repre- 

 sented (133 species) ; next the Arthropoda (106 species) , namely 

 the Crustacea, for of the small number of sea-spiders only one 

 species is yet known ; then Protozoa (73 species, of which, 

 perhaps, not a few are to be regarded as only varieties of a 

 small number of typical species) ; Annelids (57 species) ; 

 Echinodermata (36 species) ; and, lastly, Cojlenterata (22 spe- 

 cies). With regard to the last, there is the interesting and, as 

 it seems, tolerably certain conclusion that the Hydrozoa at 

 these depths are very few (only 2 species known) ; they seem 

 to be almost exclusively confined to the upper soundings, as, 

 indeed, the greatest number of those animals which are subject 

 for the most part to an alternation of generations are in their 

 last condition or generation more or less pelagic. 



It is stated by many naturalists (see Keferstein on the dis- 

 tribution of mollusks, Bronn's ' Classen und Ordnungen des 

 Thierreichs,' 1864, vol. iii. p. 1098) that the Conchifera in the 

 whole sea have a wider extension in depth than the Cephalo- 

 phora (/. e. Gasteropoda). Examination of the depths on our 

 coast contradict this statement, since the former are repre- 

 sented by 37, and the latter by 53 species, thus exceeding the 

 Conchifera by a considerable number. 



One of the rather surprising results of these present re- 

 searches is that many species Avhich are known to us as inha- 

 bitants of shoal w^ater, far from being confined to such situa- 

 tions, have a considerable range in depth, and extend from the 

 shore to the greatest depths examined on our coast. 



On the other hand, we find not a few species which, accord- 

 ing to the facts now known, are confined to the great depths. 



As such peculiarly deep-sea species I have, in my earlier 

 paper, mentioned : — the great corals Lophelia ptrolifera^ Ain- 

 phelia ramea, Ulocyathus arcticuSj Primnoa lepadifera, Para- 

 gorgia arhorea and P. grandijiora ; the great Pennatulids 



Ann. & Mag. Nat. Hist. Ser. 4. Vol. iii. 33 



