PECTUNCULUS. 



Plate VIII. 



Species 44. (Mus. Belcher.) 



Pectunculus Pectenoides. Pect. testd lenticulari, de- 

 presso-convexd, radiatim costatd; costis subobliquis, 

 compressis, depresso-planis, interstitiis eximie exca- 

 vatis; incarnato-albd, rubido-fusco profuse variegatd 

 el maculatd; intus alba, anticc fused. 



The Pecten-like Pectunculus. Shell lenticular, de- 

 pressly convex, radiately ribbed ; ribs somewhat 

 oblique, compressed, depressly flat, with the inter- 

 stices delicately excavated ; fleshy white, profusely 

 variegated and spotted with reddish-brown ; inte- 

 rior of the shell white, deeply stained with brown 

 on the anterior side. 



Deshayes, Cuv. Reg. An. (Fortin and Masson's illus- 

 trated edition) Mollusques, pi. 87. f. 8. 



Hub. Bay of Panama (found in soft mud at the depth of 

 seven fathoms) ; Hinds. 



After receiving from M. Deshayes the example of this 

 species originally described by him, Mr. Hinds supplied 

 me with finer specimens from the collection of Captain 

 Belcher. Care must be taken not to confound the Pec- 

 tunculus Pectenoides with the Pectunculi pectinatus or 

 Pectiniformis : the chief peculiarity of the species un- 

 der consideration is the flat compressed formation of the 

 ribs, and the delicate manner in which the interstices 

 between them are hollowed out. 



distinct from any other species. The hinge describes 

 an angle rather than a curve, and forms as character- 

 istic a peculiarity as the scattered faint orange spots 

 which ornament the outer surface. 



Species 45. (Fig. a and b, Musee Royale, Paris.) 



Pectunculus vitreus. Pect. testd orbicularis planulatd, 

 subauritd, tenui, longitudinaliter costatd, costis trans- 

 verse striatis ; albidd, aurantio-fusco pallide macu- 

 latd ; intus albd. 



The isrittle Pectunculus. Shell orbicular, flattish, 

 somewhat eared, thin, longitudinally ribbed, ribs 

 transversely striated ; whitish, faintly spotted with 

 orange-brown ; interior white. 



Lamarck, Anim. sans vert. (Deshayes' edit.), vol. vi. 

 p. 495. 



Hab. South Seas ? Lamarck. 



This interesting species is only known at present by 

 the single valve, here represented, in the Musee Royale 

 at the Jardin des Plantes, Paris, and which, says La- 

 marck, was from the voyage of M. Peron. It has a re- 

 markably flat brittle appearance, and is certainly very 



Species 46. (Mus. Belcher.) 



Pectunculus perdix. Pleur. testd orbiculalo-cordatd, 

 subauritd, radiatim costatd ; costis plunulutis, subin- 

 distinctis, longitudinaliter striatis, strigis rubido- 

 fuscis, transversis, angulato-undatis, profuse pictis. 



The partridge Pectunculus. Shell orbicularly heart- 

 shaped, a little eared, radiately ribbed ; ribs fiat, 

 rather indistinct, longitudinally striated, and pro- 

 fusely painted with transverse, angularly waved 

 streaks of reddish-brown. 



Reeve, Pro. Zool. Soc, 1843. 



Hab. Straits of Malacca (found in mud at the depth of 

 seventeen fathoms) ; Hinds. 



The form of this shell approximates very closely to 

 that of the Pectunculus zonalis (vide PI. IX.), but the 

 painting of it is of a very different character. The beau- 

 tiful specimen here figured, collected by Captain Belcher, 

 is the only example of the species I have seen, with the 

 exception of a small, worn, odd valve in the collection of 

 M. Deshayes. 



Species 47. (Mus. Cuming.) 



Pectunculus sf-adiceus. Pect. testd orbiculari, radiatim 

 striatd, pallide spadiced, umbones versus albd, strigis 

 latis, undatis, ornatd ; epidermide holosericd ; intus 

 albd, margine exiliter crenulato. 



The reddish-brown Pectunculus. Shell orbicular, 

 radiately striated ; pale reddish-brown, white to- 

 wards the umbones, ornamented with broad waved 

 streaks ; epidermis soft and velvety ; interior white, 

 margin finely crenulated. 



Reeve, Pro. Zool. Soc, 1843. 



Hab. ? 



There is no very striking peculiarity in this species, 

 although it is too distinct from any other to require 

 comparison. I have seen several specimens of it both 

 in London and Paris, but have not succeeded in ob- 

 taining its true locality. 



August 1843. 



