PLATE YU. 



no. 



1 & 2.— Suiirella (?) from Cambridge, Barbados. Fig. 1 possibly a 

 younii', leas developed, form of lig. 2. The slide from which 

 the fi"-. 2 was drawn was returned to Mr. Johnson, and by him 

 sent tx) IMr. Rails. Professor W. C. Williamson saw it when 

 in Mrs. Bury's hands (October, I860,) and kindly suggested it 

 might possibly lie a Surirella. 



3 & 4. — Varieties of Dictyospiris (?) Ehrenberg. 



5. Actiniscus (?) of Ehrenberg and Pritchard ; a triangular net, like 



a Diotyocha, but wth a " solid centre," which centre (or nucleus) 

 gives the idea of being capable of stretching up into a Podo- 

 cyrtis-like form ; sides of triangle measure .0065 ; there are nine 

 outer and six inner cells, arranged rouud a solid-lobed and 

 pmictured nucleus, which bears one long and two short spines. 



6. — A Desmidia-like, but silicious, clear, transparent plate, with wa^•ed 

 edges, and a perforated centre. Appears to resemble in some 

 degree, Lithodesmium undulatum, of Ehronberg's "Kroide- 

 biidung," page 76. Dr. Wallich suggested (from sketch) that 

 it might be a part only of some polycystinous form. 



"7. ^Tlie uppei' part like Ehrenberg's Podocyrtis cothurnata, but with 



a tubulous prolongation of the base. 



