REPORT ON THE RADIOLAEIA. 455 



twenty to thirty (or more ?) radial spines. (The position of this species, and the identity of 

 Chilomm.a with Astrophacomma, remains doubtful, as the imperfect figure given by Ehrenberg of 

 Chilomma saturnus, the only species of the genus, is in contradiction with his vague description, 

 as is very often the case.) 



Dimensions. — Diameter of tlie disk &1'2 (with girdle 0-:^2), of the outer medullary shell 0-05, of 

 the inner 002. 



Habitat. — Arctic Ocean (Greenland, depth 1000 fathoms), Ehrenberg. 



Subgenus 4. A-'^tropliacura, Haeckel. 



Definition. — Surface of the disk covered with radial sjiines. Bases of the ruarginal 

 spines connected by a solid equatorial girdle. 



7. Astrophacus apoUinis, n. sp. (PL 32, fig. 2). 



Disk with spiny surface, three times as broad as the outer, eight times as broad as the inner 

 medullary shell. Pores regular, circular; eleven to twelve on the radius of the disk. Equatorial 

 girdle narrow, smooth, on the margin with twelve to sixteen broad, flat, triangular spines, of the 

 same length as the numerous bristle-shaped spines of the surface, which reach half the radius 

 of the disk. (Very similar to Hdiodiscus apoUinis, but difiering in the double medullary shell.) 



Dimensions. — Diameter of the disk 0'24, of the outer medullary .shell 0'08, of the inner O'O:! ; 

 length of the radial spines 0-06, basal breadth 0'03. 



Habitat. — AVestern Tropical Pacific, Station 225, depth 4475 fathoms. 



Family XX. C o c c o d i s c i d a, Haeckel (Pis. 36-38). 



Coccodiscida, Haeckel, 1862, Monogr. d. Eaiiol., p. 485. 

 Coccodiscida, Haeckel, 1881, Prodromus, p. 458. 



LitJiocyclidina, Ehrenberg, 1847, Monatsber. d. k. preuss. AkaJ. d. Wiss. Berlin, p. 214 

 {2>artim). 



Definition.— Disc Old e a with extracapsular phacoid shell (or lenticular latticed 

 cortical shell), connected by radial beams with an intracapsular, simple or double, 

 concentric medullary shell, and surrounded l)y one or more concentric chambered 

 equatorial girdles on the margin. 



The family Coccodiscida was founded by me in 1862 for those Discoid ea 

 which agree with the Phacodiscida in the formation of the lenticular " phacoid shell " 

 (including a simple or double medullary shell), but differ from them in the develo2")ment 

 of peculiar concentric chamljered rings or girdles around the equatorial margin (jf the 

 disk, similar to those of the Porodiscida. 



The Coccodiscida represent a polymorphic family, in which we here distinguish 

 sixteen genera with fifty-seven species ; it comprises the greater part of those D i s- 



