12 



kunne havo Grund til at kakle denne Strækning Uvigeri- 

 iialer, især da denne Art her opnaar en lietydelig Stør- 

 relse, medens den paa de nordlige og østlige Dele oftest 

 er forholdsvis sjelden og degcneret. 



Det graa Ler ved Jan I\rayei) og Island synes i det 

 store 0°: hele at iiave samme Karakter som Leret ved 

 Norges Kyst. At en Art mangler snart her snart der 

 lieror vel oftest paa en Tilfældigiied og berettiger saaledes 

 ikke til at drage faste Slutninger med Hensyn til Arter- 

 nes Udiiredelse. Mange Tlialamophorer ei' jo meget spar- 

 somt repræsenteret i)aa de enkelte lokaliteter og kan vel 

 ogsaa ved et Tilfælde oversees ialfald de ubetydelige og 

 mindre ioinefuldende Arter. 



Som tidligere bemærket. har jeg delt det graa Ler i 

 2 forskjellige Udbredelsescentrer. Det nordlige af disse 

 Centrer udnirerker sig nemlig ved Forekomsten af nogle 

 arktiske Former, der enten mangler eller ialfald optiæder 

 langt sparsommere \)ixn det Omraade. der horer til det 

 sydlige Centrum. Som saadanne kan nævnes: Astrorhiza 

 crassatina, Lagena apiciilata, Pulvinulina Karstenii, og 

 Globigerina pachyderma. Pna den anden Side er der 

 ondel sydlige Arter, der inden det nordlige Centrums om- 

 raade entiMi aldeles mangler eller ialfald forekommer me- 

 get sjjarsomt og uden at opnaa sin fulde Størrelse, f. Ex. 

 Bnlimina marginata, Uvigerina pygmaea og angulosa. Oper- 

 culina ammonoides. Forøvrigt synes Talainophorfaunaen 

 over hele defc graa Ler at være meget ensformig. 



Khabdamminaleiet. Hviid der isa^- karakteriserer 

 dennt' Lersort ei' foruden dens graagronne Kulør tillige 

 dens Overflod paa Exemplarer af Rhalidammina abysso- 

 rum. Af de hyppigst forekommende Tlialamophorer kan 

 nævnes: Tholosina Inilla, Cassidnliiia laevigata, Truncatu- 

 lina lobatula og refulgeiis. Pulvinulina Karstenii, Nonionina 

 umbilicatula, Quinqueloculina seminuluni og tricarinata. 

 Forresten synes de enkelte Arter ialmindelighed at fore- 

 komme meget spredt og i ringe Antal paa hver Lokalitet. 

 Slægterne Lagena og Biloculiua. der ellers ialmindelighed 

 er ginlt representeret, udmærker sig her ved sin Fattigdom 

 paa Arter og Exemplarer. 



Globigerina buUoides, pachyderma samt talrige Over- 

 gangsformer mellem disse to Arter er alinindelige over 

 hele det graa Ler. Paa den sydlige Del af Omraadet. 

 specielt langs den norske Kyst synes de tleste Exemplarer 

 at hore til Gl. buUoides og de nævnte Overgangsfoinier, 

 medens Gl. pachyderma især er almindelig paa Rbabdam- 

 minaleret og ved Spidsbergen. 



Overgangsleret er overordentligt i'igt paa Tlialamo- 

 phorer. Specielt har jeg i en enkelt Bundprøve (fra Sta- 

 tion 192) fundet en usæ^lvanlig Mæ^ngde Arter, nemlig 

 over Halvparten af samtlige i Nordhavsexpeditionens Ma- 

 teriale forekommende Arter. Grunden til dette rige Dyre- 

 liv er vel den, at saavel de paa det grundere Vand som 

 de paa Havets Dybder levende Dyreformer her blander 



is present in particularly large numlier in the southern 

 portion of the gray clay, so that one miglit be tempted to 

 call this i'egion Uvigerina Olay, especially as that species 

 here attains a considerable size, while in the northern and 

 eastern parts it is often comparatively rare and degeiierated. 

 The gray clay near Jan Mayen Island and Iceland, 

 seems. on the whole, to have the same character as the 

 elay on the Norwegian coast. That a species is absent 

 now in one place, now in anotber, must generally be due 

 to chance. and therefore does not justify the drawing of 

 decided coiiclusion vitli regard to the distribution of tiie 

 species. Maiiy Thalamopliora. iiideed. are very poorly 

 represented in certain loealities. and may even liappen to 

 be overlooked, at aiiy rate sraaller and less conspicuoiis 

 species. 



As previously méntioiied, 1 have divided the gray 

 clay into 2 different ceiitres of distribution. Tlie more 

 northerly of these two ceiitres is eharacterised by the occur- 

 rence of some arctic forms, whicli are either absent, or at 

 any rate nppear far less frequently, in the region belon- 

 ging to the southern centre. Among these may be named 

 Astrorhiza crassatina, Lagena ajiiculata, Pulvinulina Kar- 

 stenii and Globigerina pachyderma. On tiie other hand 

 there are some southern species which are either altogether 

 aijsent from tlie field of the northern centre. or at any 

 rate are vere scarce, and do not attain to tlieir tull size. 

 e. g. Bulimi na marginata, Lvigerina pygmæa and augulosa, 

 Operculina ammonoides. Moreover, the Thalamopliora 

 fauna throughnut tlie gray clay, seems to be very homo- 

 geneous. 



The Hliabdamniina Clay. That which. in addition 

 to its gray green colour, especially characterises this kind 

 of clay, is its superabundance of specimens of Ithabdamniina 

 abyssoruin. Among the Thalamo])hora most freijently oc- 

 eurring, we may mame Tholosina iitilla. Cassidulina laevi- 

 gata, Truncatulina lobatula aiiil refulgens, Pulvinulina Kar- 

 stenii, Nonionina umbilicatula, Quinqueloculina seminulum 

 and tricarinata. The different species appear generally 

 to be very scarce, and in small iiumbers at each locality. 

 The genera Lagena and Biloculina, which are elsewhere 

 well represented. are here eharacterised by their poverty 

 of species and specimens. 



Globigerina buUoides. pachyderma, and numerous 

 transition forms between these two species are general 

 throughout the gray clay. In the southern portion of the 

 region, especially along the Norwegian coast, most of the 

 specimens seein to belong to Gl. buUoides and the above- 

 mentioned transition forms, while Gl. pachyderma is espe- 

 cially comnion in the llhaiidamniina Clay and off Spitz- 

 bergeii. 



The transition clay is exceedingly lich in Thala- 

 mopliora. In one sample (from Station 192), I liave found 

 an unusual number of species, that is to say. more tban 

 half the species occurring in the Xorth Atlantic Expedi- 

 tion coUection. The reascni for this luxuriant animal life 

 is ijrobably that the animal forms, botli in the shallower 

 water, and in the occean deptlis, niingle here, and find the 



