16 P. T. CLEVE. THE PLANKTON OF THE NORTH SEA, THE ENGLISH OHANNEL, AND THE SKAGERAK:. 



Cyttarocylis Claparedii v. Daday. ■ — As constituting this species I consider the form 

 given in fig. 1. — Rare in September at Plymouth and Helder. 



Dictyocysta elegans Ehb. — Rare in March at 6r32'N. 2°13'E. and the 31.1. in 

 the Skagerak. 



Ptychocylis aciita Brandt (or Tintinnus urnula Auct.). — North Sea: Mardi: 

 between the south of Norway and Skagen, rare. November: rare E. of Newcastle. — 

 Skagerak: rare from January to March, not rare in Novetnbei' and December. 



Fig. 1. Cyttarocylis Claparhdii v. Dad. 

 225 t. m. 



Fig. 2. Ptychocylis Ehrenhergii Clap. & Laohm. 

 225 t, m. 



P. Ehrenbergii Cl. & Lachm.? — I am unable to decide what form is represented 

 by the published figures. I believe the annexed fig. 2 represents what is understood as 

 Tintinnus Ehrenbergii, but it may perhaps also represent what some authors name Tint. 

 serratus. In all cases what I here name P. Ehrenbergii is an easily recognized neritic 

 species. It occurs abundantly in August and September at Plymouth, and from September 

 to December sparingly at Helder. 



T. beroidea var. acuminata v. Daday. — North Sea: rare in March at 55° N. 6° W. 

 Helder: rare in June, more or less scarce from September to December. The E. Channel: 

 Plymouth: rare in February to April, less rare in November, December. S:t Va,ast: not 

 rare in August, rare in December. The Skagerak: rare in January, April and May, 

 November and December. 



Tintinnopsis campanula Ehb., in Avhich species I include T. campanella v. Daday 

 and T. cinctus Cl. & Lachm., which seem to me to be the young states only. T. campa- 

 nella Hkl. is perhaps another species. 



