ATLANT. DEEP SEA EXPED. 1910. VOL. II] 



PTEROPODA. 



27 



Station 



10 



29 



34 



39 



42 



45 



49 



51 



52 



53 



56 



58 



Date 



l»/ 4 _ 21/ 4 



"Ai— 10 /s 



13 /6— "/5 



20 /5— 21 /5 



23 /o— 24 /5 



28/ 6 _29/ 5 



28° 42' 

 20° 0' 



Ve 



5 / 6 — "/« 



*/e—V« 



s h— 9 /e 



>°/e— "As 



"As— ls /« 



N 

 Position ^; 



45° 26' 

 9° 20' 



35° 10' 

 7° 55' 



28° 52' 

 14° 16' 



26° 3' 

 15° 0' 



28° 2' 

 14° 17' 



29° 8' 

 25° 32' 



31° 20' 

 35° 7' 



31° 24' 

 34° 47' 



34° 59' 

 33° 1' 



36° 53' 



29° 47' 



37° 37' 

 29° 25' 



Depth in m. 

 0— 50 

 50— 100 

 100— 250 

 250— 500 

 500— 750 

 750—1000 





















1 

 22 







5 



2 



3 



3 



3 

 2 



15 



1 



7 



2 



14 

 1 

 5 



46 

 23 



— 



— 



— 



— 



— 



— 



— 



— 



— 



— 



— 



1000—1250 

 1250—1500 



— 













1 





— 



12 



4 



— 





Station 



62 



64 



67 



69 



81 



82 



84 



87 



88 



90 



92 



94 



Date 



»/,_,«/, 



"As 



"/« 



2a 



12 ,7 



,3/ 7 



15/, 



17/, 



IS/, 



21/, 



23/,_24/, 



26/, 



Position w " 



36° 5' 

 43° 58' 



34° 44' 

 47° 52' 



40° 17' 

 50° 39' 



41° 39' 

 51° 4' 



48° 2' 

 39° 55' 



48° 24' 

 36° 53' 



48° 4' 

 32° 25' 



46° 48' 

 27° 46' 



45° 26' 

 25° 45' 



46° 58' 

 19° 6' 



48° 29' 

 13° 55' 



50° 13' 

 11° 23' 



Depth in m. 

 0— 50 

 50— 100 

 100— 250 

 250- 500 

 500— 750 

 750-1000 



12 



13 



3, 



2 

















1 



11 

 31 









2 

 2 



1 



1 



1 



12 



3 



1 

 1 



1 



11 



16 



8 



1 



6 

 12 



2 



1000—1250 

 1250—1500 



1 



1 









— 



— 



— 





— 



— 



— 



Number of individuals of Diacria trispinosa. 



as well as the northern sections across the Atlantic ocean, 

 but like all other thecosomatous pteropods, it avoids the 

 cold waters of the Newfoundland banks. 



It was taken as far north as lat. 55° 13' N. though 

 according to Meisenheimer (1905) lat. 46° N. represents 

 its normal northern limit. 



Boas (1886) distinguished two varieties of this species, 

 viz. var. major and var. minor, differing from each other 

 in size and in the position and direction of the lateral 

 spines, which in var. major are placed farther back than 

 in var. minor, and in var. major are directed obliquely 

 backwards while in var. minor they are perpendicular to 

 the long axis of the body. 



In my material both varieties are represented, but 

 although extreme specimens are very easily distinguished 

 from each other, yet there are so many transitional stages, 

 that it would be impossible to decide where the limit 

 should be drawn between the two forms. Extreme spe- 

 cimens of the var. major were during the "Michael Sars" 

 expedition found along the Spanish-African coast, while 

 the var. minor was taken at more northerly stations. 



Cavolinia (Diacria) quadridentata Lesueur. 



This little species seems to be much more limited 

 in its distribution than D. trispinosa and to inhabit 

 warmer waters. 



Like several other small pteropods it may occur in 

 dense swarms (Station 48). 



The results of the "Michael Sars" expedition with 

 regard to the distribution of this species (see the table) 

 agree perfectly well with those obtained by earlier investi- 

 gators. (Meisenheimer 1905). 



Station 



48 



49 



50 



52 



53 



67 



Date 



31 /s 



'A 



Ve 



"As- 7 /* 



s As— 9 As 



N 

 Position yj 



28° 54' 

 24° 14' 



29° 8' 



25° 16' 



30° 8' 

 31° 19' 



31° 24' 



34° 47' 



34° 59' 

 33° r 



40° 17' 

 50° 39' 



Depth in m. 

 0— 50 



64 





1 



1 





1 



50- 100 



— 



— 



— 



2 



1 



— 



100-- 250 



— 



— 



— 



— 



— 



— 



250— 500 



— 



— 



— 



— 



— 



— 



500— 750 



— 



— 



— 



— 



— 



— 



750—1000 



— 



— 



— 



— 



— 



— 



1C00— 1250 



— 



— ' 



— 



— 



— 



— 



1250-1500 



— 



3 



— 



— 



— 



— 



Number of individuals of Diacria quadridentata. 



Subgen. 2: Cavolinia s. str., Abildgaard. 



The relation between this subgenus and Diacria is 

 obvious, and has been often discussed by earlier authors. 

 I shall here only mention that the characters connecting 

 Diacria with Clio falcata are somewhat Teduced in 



