Kreletoiienia costatum (Greg.) Ci,. 



Distribidion : Very frequent on the west coast of Norway, 

 often in lai-ge quantities. Occurs all the year round, but varies 

 very much in quantity. On the north coast April— May ; here too 

 there are very great variations in quantity. Also more or less 

 frequent on the northei'n European coasts of the Atlantic and its 

 arms. Known too from a few places on the tropical coasts (Ben- 

 gal, Java, Hongkong, The West Indies) and from Japan. 



Paralia sulcata (Kbrb.) Cl. 



Hardly a true plankton form, at any rate not with us. Is 

 vei-y frequent in bottom samples (cfr. the corresponding chapter) 

 from Nordland and Finmarken. The few specimens which have 

 been found in plankton samples, especially from deep water near 

 the bottom, have probably come there quite by accident. The numer- 

 ous valves which are found in bottom samples, cannot be considered 

 to come from plankton, for then one would expect to find the 

 species, at any rate occasionally, numerous in plankton samples, 

 which is, however, as far as my experience goes, never the case, 

 at least with us. Nothing is proved either by the presence of a 

 few solitary individuals in samples taken far from the bottom, as 

 such individuals may have been bi-ought there with algæ which 

 have been torn away or — when they are found in diatom slides 

 — may have been swallowed by Crustacea or similar small animals. 



Distrihut'wn : Frequent on the northern coasts of the Atlantic 

 (on the American side from the coast of Central America) right up 

 to Greenland and Franz Joseph's Land. Mentioned as occurring 

 (February 1903) now and then in abundance in surface samples 

 from the English Channel (L. 18). 



Il>alodlsoii!« Ehkb. 



H. scoticits (KiiTZ.) Grun. 



No true plankton foi'ni. Frequent in bottom samples (cfr. the 

 coi'i-esponding cliapter). 



H. siihtilis liAti.. 



liAih. L. 8, p. 10. f. 12. 



In a plankton sample from Malangen '"A 1899, 0—300 m., 

 a few single specimens were found which seemed to belong to this 

 species. 



Hardly any true jjlunkton form. 



H. stuinger Baii,. 



Doubtful as a true plankton form. Neither is it frequent in 

 bottom samples. Perhaps come in with algæ. 



Distribution: The northern European coasts of the Atlantic 

 and its arms. 



On the west coast of Norway found all the year round in 

 plankton, but always in small quantities. Mentioned from the 

 English Channel in surface samples, occasionally numerous (especi- 

 ally in February 1903), often together with Paralia sulcata. 



3. Eupodisceæ. 



Roperia Ghun. in Van Heurck. 



(L. 88. pi. 118). 



R. tessellata (Rop.) Gruj 



-7. Eujiodiseus tcssellatus Rop. L. 

 Adinocydus tessellatus Ralfs in 



Geun. 1. c. pi. 118, f. 6- 

 126, p. 19, pi. 3, f. 1 a, b. 

 Peitch. (L. 123) p. 835. 



Peculiar structure (cfr. Van Heukck's Synopsis). It seems, 

 however, that it may well be included, at any rate as a subgenus, 

 in the genus Adinocydus. 



This beautiful species occurs only singly and rarely in the 

 plankton, in deep water samples in 1899: — 'Vi The Vest Fiord 

 I, 0—180 m.; "/i Senjen, 0—130 m.; ^'A Henningsvær, 0—250 m. 



Distribution: Occurs, according to Cleve, on the coasts of 

 Scotland. Scarcely a literal, but certainly a true plankton form. 

 Also known from the coasts of France and England. It has most 

 Ukely been overlooked, and is probably more frequent than the 

 few places mentioned would indicate. Also occurs on the west 

 coast of Norway, but seldom (Feb. 1899). I have also seen it in 

 oceanic plankton samples outside the noi'th west coast of Norway 

 (S/S Michael Sars 1901). 



Judging from its occui'rence with us, it gives the impression of 

 being a temperate, Atlantic, oceanic species. 



AuliHcniii Ehrb. 

 L. .54, p. 270. 



A. sculptus (W. Sm.) Ei 



pi. 6, f. 3. Van Heueck 

 zulptus W. Sm. L. 134, I, 



Ralfs in Peitch, (L. 123), p. 845, 

 L. 88, pi. 117, f. 1 — 2. Eujwdiscus s, 

 p. 25, pi. 4, f. 39. 



No true plankton form. Frequent in bottom samples, both 

 from the northei'n and western coasts of Norway. (Cfr. the corres- 

 ponding chapter.) 



4. Asterolauipreæ. 

 Artiiiopt.^'diiis iiiiiliilatiis (Bail. y) Rai.ks. 



I am not sure if this species really is a tiue plankton form. 

 It occurs especially in deep water samples and always very scar- 

 cely. It is not numerous in bottom samples either. 



Distribution : Has a wide distribution on the northern Euro- 

 pean coasts of the Atlantic and its arms, and is found right up to 

 Greenland. Is not considered by Cleve and Ostenfeld to be a 

 genuine plankton form. 



Is mentioned (L. 18, IV) as occasionally frequent in surface 

 samples from the English Channel (Feb. 1903). In the same 

 samples, other doubtful plankton forms, such as Paralia sulcata 

 and Byalofliscus sMUiicr, also occur more or less frequent. 



AKtoi'»lil|>liallis hvptactis (Bhéb.) Ralfs. 



Very rare: January 1899, especially in deep water samples. 

 Distribution: With us a southern, oceanic species, which is 



