KONGL. SV. VET AKADEMIENS HANDLINGAR. BAND. 19. N:0 4. 



117 



0^virIg to tlic; scarcity ol our supply of speciuicus we are not able to make an 

 even approximately correct and critieal survey of the several (about 40) described 

 »species» of Pulyst. crispa but refer tlie student to the able and interesting anangenient 

 of this genus devised by Messrs Parker and Jones in tlieir adniirable treatise oii Fo- 

 ranif. of North Atlantic and Aretic Oceans; Phil. Träns. 155. 1, p. 400. 



It has beeii niet with in the chalkooze only. 



Heterostegiiia tlepressa dOrb. var. simplex dOrb. 



Tab. VIII, tigg. 303. 



This form comes next to Heterostegina curva MöB. (from Mauritius), whieh is a 

 weak form of Heterost. depressa with few and large chamberlets. Our form is very thin 

 and gives at iirst sight the impression of a starved and miscarried Amphistegina, with 

 which as to shell-siibstance and pores it has iiiuch in eommon. 



It is very seldom met with, but reaches a pretty good size on both the coralline- 

 gravel and the chalk-bottom. 



Fig. 303: viewed in transmitted light. 



a) Sep tis secun dariis paiicis: 



Syu. Heterosteg. simplex 

 )) curva 



i)'Oitii., l«4(j, Kor. tert. Vieiuie, p. 211, t. 12, tigg. 12 — 14. 

 Möii., 1880, Maui-. u. Seychell. p. 105, t. 13, tigg. 1—5. 



b) S e p t i s s e c u u d a r i i s n u m m e r o s i s : 



Heterosteg. depressa u'Orh., 182G, Tab. inétli.; An. Se. Nat. 7, p. 305, Mod. 99; t. 17, tigg. 



5—7. 



» Antillarum u'OiiB., 1839, Cuba, p. 122, t. 7, tigg. 24—25. 



» costata d'Orb., 1846, For. tert. Vieiiue, p. 212, t. 12, tigg. 15 — 17. 



» « Fitijs Mod. 100. 



" reticulata (lliJTiGM.) IIken., 1875, For. Clav. Szab. Sch. p. 81, t. 12, (ig. 3. 



Gen. indef. Costa, 1854, Pal. Nap. 2, t. 20, tig. 15. 



PHeterosteg. Grotriani Rss., 18ö5, Ueutsch. Septarienthou; Wieu. Ak. Dkschr. 1. 25. p. 164, 



t. 4, tig. 18 (an Operculina complanata Defk.). 



Aiupliistogina vulgaris dOkb. 



Is very eommon in the coralline-gravel and attains a diameter of 3 mm. and 

 more, with many gradations in tlie relation between the length of the vertical and 

 horizontal diameters. It seems on our bottom to substitute genus Nummidimi, of 

 which no trace lias appeared, even in the shape of Operculina. 



