ZIKFyEA. 39 



across the disk, and it has a dorsal valve of which P. crispata is 

 destitute. 



The animal is of a dark, smoky color ; the sijjhon is tapering, not 

 very long, and circularly wrinkled ; respiratory orifice striped alter- 

 nately black and white, the latter stripes marking the presence of 

 fourteen tentacular organs. 



Oenus ZIRF.EA, Leach (G-ray). 1840. 



Shell oval, hinge margin scarcely reflexed, joined by a horny 

 epidermis without accessory pieces, widely gaping in front. 



Zirfsea crispata. 



Valves touching at the middle of the base, and Avidely gaping at both ends; 

 a furrow passes from the beaks across the middle, in front of which are radi- 

 ating, toothed ribs. 



Pholas crispata, Linn. Syst. Nat. j). 1111 (1758). — Gmelin, S^vst. p. 3216. — Sowerby, 

 Thcs. Conch. — Cuv. Regnc An. (Griffiths) pi. 113, fig. 3 (animal). — Brown, 

 111. Conch. 114, pi. 48, figs. 1 -5. — Hanley, Rec. Sh. 7, pi. 2, fig. .'5; Ipsa Lin. 

 Conch. 26. — McGiLLiv. Moll. Abcrd. 306. — Thorpe, Br. M. Conch. 29. — Dr 

 Kay, Nat. Hist. New York, 247, pi. 32, fig. 506. — Loven, Ind. Moll. Scaiid. 

 50. — Forbes and Hane. Br. Moll. i. 114, pi. 4, figs. 3-5. — Donovan, Brit. 

 Shells, ii. pi. 62, 69. — TuRTON, Brit. Biv. 6; Conch. Diet. 146; Linn. Trans, 

 viii. 32. — Hutch. Dorset Catal. 27, t. 3, fig. 4. — Wood, Gen. Conch. 81, pi. 15, 

 figs. 3-5 ; Index, pi. 2, fig. 5. — Dillw^yn, Descr. Catal. 40. — Desha yes, Eneyc. 

 Me'th. Vers, iii. 754, pi. 169, fig.s. 5-7. — Lamarck, An. sans Vert. vi. 46. — 

 ScHROT. Einl. in Conch, iii. 541, No. 6. — Petiver, Gazoph. t. 79, fig. 13. — Flem. 

 Br. An. 456. 



Pholas hifrons, Da Costa, Brit. Conch. 243, t. 16, fig. 4. 



Phofas latus, Lister, Conch, t. 436, fig. 279, and Append, t. 10, fig. 3. 



Solen crispus, Lin., Gmel. Syst. 3228. — List. Angl. t. 5, fig. 38. 



Pholas crispatus, Pennant, Brit. Zool. iv. 157, t. 43, fig. 2. — Montagu, Test. Brit. 23. — 

 Chemn. viii. 369, t. 102, figs. 872-874. 



Zirphaa crispata, Chenu, Man. de Conch, ii. 6, figs. 26, 27. — Adams, Gen. ii. 327, ])1. 

 89, fig. 5. 



ZirfcEa crispata, Gray, Cat. Br. Mns. (Biv.) 53. 



Shell oblong-oval, thick and strong, rounded posteriorly, nar- 

 rowed anteriorly into a sort of beak ; widely gaping at l)oth ends, 

 the valves touching each other at only two points, viz. the hinge 

 and the middle of the base. Exterior surface marked with numer- 

 ous coarse, concentric ridges, which become lamellar on the ante- 

 rior half; the laminas are strongly toothed on their free edge, and 

 the teeth are disposed in radiating series. Tlie valves are divided 

 into two nearly equal portions by a liroad channel running from 



