106 G0É8, RETICULARIAN RHIZOPODA OF THE CARIBBEAN SEA. 



Syn. PDiscorbina baeonica, elegans Hken., 1875. Clav. Szåb. Sch. p. 76, t. 10, fig. 3, t. 9, fig. 3, t. 15, 



fig. 7. 

 B eximia Hken., ibid. p. 76, t. 15, fig. 8. 



Discorbina turbo d'Orb. et multte iilipe troohiformes ;iuctorum a rosaeea forsau nou sunt 

 distinctfe. 



Discorbina valvulata d'Oeb. 



Tab. VIII, figg. 258—261. 



Although this foi'ra has been placed as a variety under Discorb. vesicularis Lmck, 

 by Messrs Parker and Jones, it may be proper to di.stinguish it as a species in virtue 

 of its peculiarl}' formed shell. It is identical with Rosalina Binkhorsti Rss. from the 

 Maestrich-chalk, and is remarkable for the fewness and the large size of its chambers, 

 its hoUowed apertural side, which is of simpler structure than usually, not being com- 

 plicated with additional »asterigerine» flaps, having no more than a narrow valvular 

 strip on the upper margin of the aperture. 



It attains a pretty good size, occuri'ing only in the coralline-gravel. 



Figg. 258 — 259 : the spiral side. 



Fig. 260: apertural side. 



Fiff. 261: edge-view. 



Syn. Bosalina valvulata d'Orb., 1826, Tabl. meth. Ann. Se. Nat. 7, p. 271. 



» » d'Oi{B., 1839 Ciiba p. 96, t. 3, figg. 21—23. 



» Binkhorsti Ess., 1861, Kreidetuff Maastricht; Wien. Ak. Sitz.-Ber. 1. 44, p. 317, t. 2, 



fig. 3. 

 PEotalina patella Rss., 1849, Neue For. Wien. Beck.: Wien. Ak. Dkschr. 1. i, p. 371, t. 46, 



fig. 3 (an D. Berthelotiana). 

 Discorb. stellata, squamula Rss., 1867, Steinsaizablag. Wieliczka; Wien. Ak. Sitz.-Ber. 1.55, p. 101, 



t. 5, figg. 1 — 2 (an D. rosaeea). 



Discorbina bulloides dOrb. 



Tab. VIII, fig. 262—263. 



I am not able to find any satisfactory reason for a generic nay even for specific 

 di.stinction between Discorbina rosaeea and this form, which has been referred to the 

 genus Cymbalopora (Hagenow) by Messrs Parker, Jones and CAiiPENTER. 



This however seems to have very small affinity to our form — if any at all. 

 (See also Schwager in Btltchlis' Klassen und Ordnungen des Thierreichs 1881, p. 256.) 

 Prof. MoEBius has carried the separation from its natural relations still further by 

 assigning it a place in a new genus, Tretomphalus ; (Meeresfauna Mauritius und Sey- 

 chellen; foramf. p. 98, t. lU, figg. 6 — 9). The pores of various sizes on the last seg- 

 ment should not be regarded as a mark of generic nor of specific distinction. If this 

 globular chamber is detached, the rest will hardly be distinguished from D. rosaeea. 



