800 



SYSTEMATIC HISTORY OF THE II^PUSOEIA. 



tortuous, gi'adually smooth in the cen- 

 tre ; costse numerous, continuous, their 

 crest acute. KSA. p. 33. Aquatic. 

 Asia 5 Salzberg. Fossil at San Fiore. 

 Kays 7 in 1-1152". B. 432". 



C. Kiltzmgu(B,). — Disc saddle-shaped, 

 broadly margined, marked with about 

 50 transverse, continuous, cm*ved sulci. 

 B. in Proc. Acad. Phil. 1853. Philippine 

 Islands. 



C. Ralfsii (S.). — Disc small, subcir- 

 cular, bent; costae transverse, reaching 

 the median line. SBD. i. p. 30, pi. 30. 

 f. 257. Marine. Britain. The costse of 

 one side are divided from those of the 

 other by a longitudinal median line. 



C. Nonncmicus (Gr.). — Costae 3 to 4 in 

 •001", imperfectly radiant, passing across 

 a linear-oblong central depression to the 

 narrow median blank line. G-r TMS. 

 viii. p. 29, pi. 1. f. 1. West Indies. 



C. notatiis (Gr.). — Costse numerous, 

 about 12 in -001", in length more than 

 half the radius ; central space oval, with 

 a median thick bar dilated at each end. 

 Gr TMS. viii. p. 31, pi. 1. f. 4. Shell- 

 cleanings. Distinguished by the mark- 

 ings of the centre, which Mr. Norman 

 aptly compares to the figure of a dumb- 

 bell, Gr. 



C. clecorus (Breb.). — Disc circular, bent, 

 with a simple series of long, arcuate costae, 

 and a smooth, narrow-lanceolate median 

 space. BDC. p. 13. f. 2. = C. Ralfsii? 

 GDC. p. 30, pi. 3. f. 52. Marine. France, 

 Britain. " This species is very elegant. 

 Its costse are, with the exception of 

 one or two central, all curved towards 

 the ends," Breb. The following re- 

 marks are from Dr. Gregory's paper : — 

 " I have referred it to C. Ralfsii, S., al- 

 though it is much larger than the form 

 figured by him, and although there are 

 other differences. Thus in C. Ralfsii the 

 canaliculi reach the median line, and the 

 row of heads or expansions lie some di- 

 stance from the margin. But these dif- 

 ferences cannot be regarded as specific." 



C. angularis (Greg.). — Disc suborbicu- 

 lar ; costse very numerous (160 or more) 

 and unequal, imperfectly radiant, form- 

 ing a simple marginal band, and divided 

 into two sets by prolongations of the 

 large, oval central smooth space. GDC. 

 p. 30, t. 3. f. 53. Loch Fine, Scotland. 

 Named from the angular bending back 

 of the valves. The costse are longest at 

 the middle of each side ; and, as in C. 

 decorus, all except the central ones are 

 curved, with the concavity towards the 

 ends, and become also gradually smaller 

 on approaching them. " A true median 



line is visible, but is very delicate 



The surface of the valve, both above and 

 below — that is, near both ends of the 

 median line — is suddenly bent back, so 

 as to fomi an angle with the rest of the 

 valve. On the surface thus bent, short 

 lines appear between the costse," Greg. 

 Distinguished from C. decorus by its more 

 numerous costse, oval central space, and 

 extensions of the latter separating the 

 costse into two sets. 



C. Hodgsonii (S.). — ^Disc subcircular, 

 bent, with a marginal series of very nu- 

 merous (100 or upwards) imperfectly- 

 radiating costse ; the central space with 

 transverse rows of dots divided by a 

 narrow median smooth line. SBD. i. p. 

 29, pi. 6. f. 53. Marine. Britain. ^^The 

 smooth median line is formed by a ridge 

 and two continuous furrows passing 

 across the valve," Smith. The costse 

 near the ends converge. Mr. Boper finds 

 the dots vary greatly in number, distinct- 

 ness, and arrangement, especially in the 

 larger specimens, and on this account 

 considers C. eximius not distinct from it. 



C. concinnus (Grev.). — Costse 5 in 

 •001", radiant, forming a narrow mar- 

 ginal band ; central area oval, furnished 

 with numerous transverse moniliform 

 strise, interrupted by a median blank line. 

 = C, marqinatus, Johnst. inMJ. viii. p. 13, 

 pi. 1. f. 11; GrTMS. viii. p. 8, f. 2. Shell- 

 scrapings. New Providence. Californian 

 guano. 



C. eximius (Greg.). — Disc subcircular, 

 bent ; costse strong, very numerous (often 

 150), rather short, in a single marginal 

 subradiating circle, enclosing a large hya- 

 line space, furnished with scattered gra- 

 nules and a median line. GDC. p. 31, 

 pi. 3. f. 54. Marine. Loch Fine, Scot- 

 land. The costse of C. eximius, like those 

 of C. Hodgsonii, are rendered imperfectly 

 radiant by the convergence of those near 

 the end of the median line or raphe. 

 C. eximius differs from that species in its 

 less conspicuous and scattered granules, 

 invisible except when highly magnified. 

 Mr. Roper, however, may be right in re- 

 garding it as a variety of C. Hodgsoniiy 

 since Professor Gregory himself states 

 that the granules " in some instances 

 show faint traces of a linear arrangement 

 close to the marginal band." 



2 * Disc circular or subcircular, with a 

 double concentric series of costcB. 

 C. centralis (Greg.). — Disc with about 

 forty, equal radiating costse, leaving a 

 small umbilical space ; the costse conti- 

 nuous, but divided into two series by a 



