12 Acta Societatis pro Fanna et Flora Fennica II. 



C. crenatum Ralfs. Kakskerta. 



— — ^ siihcrenatum Rabenh. Pargas. 



C. calcareiim Wittr. Kakskerta. 



C. cycllcum Lund. Nadendal. 



o 



0. umhdatiim Corda. Abo, Kakskerta, Karkku. 



C. sexanguJare Lund. Pargas. 



C. (jotlandicum Wittr. Kakskerta, Nadendal. 



C. nitkliiliim DeNot.(?). Forma e Karkku, utrum hujus spe- 

 cie! sit necne incertus; delineavi earn in fig. 7. — Longit. 28 ^u, 

 latit. 26 /Y, latit. isthmi 15 ^/, crassit. 10 ^. 



C. retusiim Perty. Karkku. Forma »dorso minus protractor 



o 



(Lund). Abo, Nadendal. 



C. venustum (Breb.) Rabenh. Pargas. — In Pargas et Karkku 

 forma quoque adest, quam Reinsch sub nomine Didymidii (Cos- 

 marii) Braunli B. a. descripsit. 



C. Hammeri Reinsch « major Reinsch. Pargas. 



o 



C. clepsydra Nordst. Abo, Kakskerta, Karkku. 



C. profuberaiis Lund. Karkku. 



C.^tetrachondrimi Lund. Karkku. 



C. depressiim (Naeg.) Lund. Kakskerta. 



C. hexagonum n. sp. 



C. parvum, diametro circa sexta parte longius, profundis- 

 sime constrictum, sinu lineari, nee ampliato. Semicellulae sub- 

 hexagonae, basi rectae, dorso truncatae, angulis basalibus fere 

 rectis, lateralibus et apicalibus obtuse rotundatis; a vertice visae 

 ellipticae; a latere visae subcirculares; membrana glabra. Lati- 

 tudo isthmi quadrans diametri longitudinalis. Crassitudo corporis 

 dimidium longitudinis. Nuclei amylacei singuli. 



Long. 28—30 ,w, lat. 24 — 27 /;, crass. 15 //, lat. isthmi 7 — 

 8 ^. — Fig. 8. 



Abo. 



o 



C ohsoletinn Hantzsch. Abo. 



C. faxichondriim himd. Abo, Kakskerta, Nadendal, Karkku. 



o 



C. imchydermum Lund. Abo, Karkku. 



— — ^ minus Nordst. Kuusamo. 



C. perforatum Lund. Abo, Nadendal, Karkku. 



C. pyramidatum (Breb.) Lund. Abo, Nadendal, Karkku. 



C. pseudopyramidatiun Lund. Satis frequens. 



C. laeve Rabenh. Karuna. 



