KONGL. SV. VET AKADEMIENS HANDLINGAK. BAND. 19. NH) 4. 117 



Owing to the scarcity of our supply of specimens we are not able to make an 

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

 species of Polyst. crispa but refer the student to the able and interesting arrangement 

 of this genus devised by Messrs PAKKEH and JUNES in their admirable treatise on Fo- 

 ramf. of North Atlantic and Arctic Oceans; 1'hil. Trans. 155. 1, p. 400. 



It has been met with in the chalkooze only. 



Ilcterostcgiiui dcpressa D'OKB. var. simplex D'OKB. 



Tab. VIII, iigg. 303. 



This form comes next to Heterostegintl curva MOB. (from Mauritius), which is a 

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

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

 which as to shell-substance and pores it has much in common. 



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) Septis secundariis paucis: 



Syn. Heterosteg. simplex D'OKB., 1840, For. tert. Vienne, p. 211, t. 12, figg. 12 14. 



curva MOB., 1880, Muur. u. Seychell. p. 105, t. 13, figg. 1 5. 



b) Septis aeoundariu u u HI m e r o s i s : 



Heterosteg. depressa D'OKB., 1826, Tab. meth.; An. Sc. Nat. 7, p. 305, Mod. 99; t. 17, figg. 



57. 



Antillarum u'Oim., 1839, Cuba, p. 122, t. 7, figg. 2425. 



costata u'C-RB., 1846, For. tert. Vienne, p. 212, t. 12, figg. 15 17. 



FKU;S Mod. 100. 



reticulata (RiJTiGM.) HKEN., 1875, For. Clav. S/ab. Sch. p. 81, t. 12, fig. 3- 



Gen. indef. COSTA, 1854, Pal. Nap. 2, t. 20, fig. 15. 



PHeterosteg. Grotriani Rss., 1865, Deutsch. Septarienthon; Wien. Ak. Dkschr. 1. 25. p. 164, 



t. 4, fig. 18 (an Operculina complanata UEFU.). 



Aiuphistegimi vulgaris D' 



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

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

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

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



