306 Ove Paulsen. 



Ooniodoma Stein. 



6. Goniodoma Ostenfeldii Paulsen, Plankton invest. Iceland 

 1903, p. 20, flg. 2; Nord. Plankton p. 34, fig. 43; Broch Spitzbergen 

 Plankton p. 32, fig. 3. 



Found in single specimens in Danmarks Havn, the coastal water, 

 and the open sea. 



D i strib. Arctic, neritic si)ecies, known from North-Iceland and Spitz- 

 bergen. 



Peridinium Ehrenberg. 



Of late years difTerent methods of shortly designating the plates 

 composing the skeleton of Peridinium have been proposed. The first 

 was that of Faure-Fremiet, whose paper "Etude descriptive des péri- 

 diniens et des infusoires ciliés du plankton de la baie de la Hougue" 

 was published in 1908 in Annales des sc. naturelles, zoologie. Fauré- 

 Fremiet designates the plates by letters with annexed numbers, so 

 e. g. the precingulars are named d^ — d^, d^ being to the right, do 

 to the left, dg to the right and so on. This method seems to me 

 not to be practical. 



Next to Faure-Fremiet comes Kofoid, the well-known investiga- 

 tor of the Dinoflagellates. His paper "On Peridinium Steini Jørgen- 

 sen, with a note on the nomenclature of the skeleton of the Peridi- 

 nidae" was published in 1909 in Archiv für Protistenkunde 16. Kofoid 

 employs only numerals, the different series of plates being distingu- 

 ished by different numbers of apostrophes or other signs annexed 

 to the numerals. So, the apicals are 1'— 4', intercalaries 1" — 3°, 

 precingulars 1" — 7", postcingulars Г"— 5'", antapicals 1"" — 2"". Each 

 series begins on the left side of the body and goes round it to the 

 right side. This system is a clear one, but not very practical be- 

 cause of the apostrophes as to whose numbers mistakes are likely 

 to arise ^ 



Broch in his paper on Spitzbergen plankton (1910) gives a new 

 method of designating the plates. He uses both numerals and let- 

 ters. In the same year the method was modified in "Die Peridi- 

 nium-Arten des Nordhafens (Val di Bora) bei Rovigno im Jahre 1909" 

 (Arch. f. Protistenk. 20). Here, the apicals are named 1—4 and the 

 precingulars a— g, 1 being the rhomb-plate and a the precingular 

 neighbouring it to the left, and both series go round the body to 



1 From the table where Коьош has arranged previous nomenclatures it appears 

 that he has not realized the difference between „tafeln" and „platten'- as these 

 termini were used by Schutt and after him also Ijn' the present author who in 

 Nord. Plankton did use Schitts nomenclature. It might have been mentioned 

 that ScHi'TTS „tafeln" represent transverse series of „plates". Only the inter- 

 calaries were not recognised as a series b}' SchTtt. 



