OF THE COCCONEIDE^. 



871 



dinal fascia, bisected by median line and 

 nodule. 



C. Brimdusiaca (Rab.). — Very large, 

 -w-ith very convex dorsimi ; disc elliptic- 

 oblong, witli from 22 to 24 someT\^liat 

 diverging, transverse, gTanulated costte, 

 and an oblong central blank space bi- 

 sected bv a linear median line. Eab D. 

 p. 28, t. 3. f. 16. 



C. margaritifera (E.). — Broadly ovate, 

 with subacute ends and transverse gTa- 

 nulated striae like rows of pearls. Marine. 

 Bosphorus, South Africa. It is closely 

 allied to C. Americana, but is rather 

 larger and not curved. 



C. nitida (Greg.). — Broadly oval, with 

 suddenly contracted, subacute, short, 

 point-like apices, transverse rows of 

 very large pearl-like granides, and a 

 narrow-lanceolate blank median space. 

 GDC. p. 20, pi. 1. f. 26. Scotland. The 

 granules are so aiTanged as to form both 

 longitudinal and transverse series. With- 

 out the central nodule, which we have 

 not detected, this species agrees with 

 Ehaphoneis. 



3 * Lateral vieiv rhomboid. 



C. rhombea (E.). — Rhomboid, with 

 about three longitudinal lines on each 

 side the median suture. EM. pi. 35 a. 7. 

 f. 2. Aquatic. Niagara. 1-1200". Re- 

 sembles C. Americana. With the excep- 

 tion of the median line and nodule, 

 Ehrenberg's figure has no markings. 



C. Americana (E.). — Small, rhomboid, 

 with somewhat produced obtuse apices 

 and faint (sometimes obsolete) dotted 

 transverse striae. KSA. p. 53. C. Mexi- 

 cana, EA. t. 3. 5. f. 7. Mexico, (xii. 48.) 



4 * Strice decussating. 



C. decussata (E.). — Large, broadly 

 elliptic, rough with decussating series of 

 apiculi. KB. p. 73, pi. 28. f. 17. Cuba, 

 India. 



C. rhomhifera (B.). — Broadly elliptic 

 or suborbicular, with a sigmoid, ob- 

 liquely longitudinal median line, run- 

 ning through a smooth space, attenuated 

 at the ends and enlarged at the nodule 

 into a rhomboid figm-e; sm-face decus- 

 sately and transversely pimctate. Bail. 

 in Proc. Acad. Philad. 1853. Puget's 

 Sound. 



5* StriiB transverse, separated into two 

 series on each side the median line by a 

 blank longitudinal fascia. 



C . pseudo-inarginata (Greg. ) . — Large, 

 broadly elliptical, with median line and 

 nodides having- on each side fine trans- 



verse striae, intermpted and separated 

 into two series by a lonsitudinal blank 

 fascia. GDC. p. 20, pi. 1. f. 27. (vn. 39.) 

 Scotland. Thin, transparent, the ends 

 less rounded than in many species, me- 

 dian line not reaching the extremities, 

 and enclosed in the lanceolate space 

 formed by the convergence of the two 

 lateral fasciae. 



C. tceniata, EM. pi. 6. 2. f. 12. Fossil. 

 Morea. We have seen no description of 

 this species. The figure represents it as 

 elliptic, having its transverse striae di- 

 vided into two series on each side the 

 median line and nodule by a longitu- 

 dinal blank fascia, as in some species of 

 Na^dcida. 



6 * Disc icith longitudinal concentric lines 

 interrupted by radiating costce. 



C. radiata (Greg.). — Elliptic, with 

 rounded ends, about 8 concentric lines 

 inteiTupted by nimierous (18) strong 

 rays proceeding from the umbilical 

 nodule. Greg TMS. v. pi. 1. f. 26. 

 Scotland. 



C. costata (Greg.). — Valve oval, rather 

 broad, median line conspicuous, nodule 

 obsolete, marked with strong entire 

 costse reaching from the median line to 

 the margin; spaces between the costas 

 striate ; striae at right angles to the 

 costae. Glenshira sand. Greg TMS. v, 

 p. 68, pi. 1. f. 27. 



7* Median line and nodule excentric. 



C. ? excentrica (Donkin). — Suborbicu- 

 lar, divided unequally by the median 

 line, which does not reach the margin, 

 and fm'nished with fine, dotted, trans- 

 verse, converging striae. Donkin, TMS. 

 vi. pL3. f. 11. Marine, (vn. 40.) North- 

 umberland. One of Dr. Donldn's in- 

 teresting discoveries, remarkable for the 

 excentric position of its median line and 

 umbilical nodule, and probably the type 

 of a new genus. The striae converge 

 towards the umbilicus, their pimcta near 

 the margin are closer and more distinct, 

 forming a broad border. 



8 * Transverse strice and conspicuous 

 margin. 



C. coronata (Bri.). — Valve oval ; striae 

 transverse, reaching the conspicuous 

 median line, smToimded by a costate 

 band; spaces between the costae punc- 

 tate; costae about 9 in -001"; striae 15 

 in -001". Bri JMS. vii. p. 179, pi. 9. f. 3. 

 Shell cleanings. West Indies. The me- 

 dian line reaches only to the margin of 

 the band ; breadth of band -0002". 



