48 



TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



deposit was formed almost wholly of enormous numbers 

 of a very active little Peridinian or Dinoflagellate of a 

 bright yellow colour (figs. 23 and 24). More careful 

 investigation, in which Mr. Eiddell and Miss M. 

 Latarche helped me, enabled us to identify this form as 

 Ami)hidinliim oijercvlatuvi, described by Claparede and 

 Lachmann, in 1858, from specimens obtained at 

 Christiansand, Bergen, and a few other places in 

 Norway. 







»^'^?* 



Fig. 23. Sand-grains and Amjihi- 

 (iiniion (photo-micrograph under 

 low-power magnification). 



I'l-. iM. Part of Fig. 28 under 

 liigii-powcr raagniiication. 



'■ The pul)]isli('(l records of A/ii ///lidiii i inn , liowever, 

 do not give the im])ression lliat il is a connnon or 

 abundant organism. Tlic hitest comprehensive work on 

 such forms — the article on Peridiniales, by Paulsen, in 

 the ' Nordisclies Plankton ' (Kiel, 1908) — recognises four 

 species of Awjihidi/ninn: .\ . crassu ni , A. rof iniddt u di , 

 and A. lon<)um, whicli as yei Iiavc been recorded from 

 Kiel 07ily; and .4. operculatuin, which is stated to occur 

 in ])rackis]i water on the north coasts of Europe, In 



