CATALOGUE—SHELLS. 549 
described has a rounded form; the bows or front being rather 
elegantly and finely lamellated in a wavy form; the colour of the 
hinge is red, and the inside is generally of a brownish purple ; in 
some it has a more yellow tinge. 
13. ARCA PECTINOIDES. 
A. testd auriculatd, cordatd, ventricosd, multi-costatd, transversim 
striatd, alba, epidermide rufo nigricante, pilosd ; wmbonibus sub- 
approximatis, incurvatis, margine crenulato; long. 1; lat. 12 ; 
poll. 
Habitat ad Rio de Janeiro. Mus. Brit., nost., Brod. 
14, NucuLA sTRIATA. 
N.testé striatd, subtumidd, crassd, sub-trigond, albd; latere antico 
productiori, sub-rostrato; long. 25; lat. 3; poll. 
Habitat in mari alto circa oras Patagonicas. Mus. nost. 
Taken by a dredge in 40 fathoms water, 20 miles from the coast 
of South America, in the neighbourhood of Port Sta Elena. 
15. Moproia stnuosa. 
M. testé ventricosd, subovatd, longitudinaliter striaté; intus wrides- 
cente, margine sinuoso, epidermide fuscd; long. J, ; lat. +4 fere ; 
poll. 
Habitat ad littora Brasilia (Santos). Mus. nost. 
16. Prcren ParacnHonicus. 
P. testd sub-aquivalvi, brunned, longitudinaliter creberrimeé elevato- 
radiatd ; intus albidd, longitudinaliter sub-radiaté ; long. 24; 
lat. 24; poll. 
Obs. auribus inequalibus. 
Habitat in freto Magellanico passim. Mus. nost. 
17, PECTEN VITREUS. 
P. testd subequivalvi, translucente, longitudinaliter multi-sulcatda ; 
sulcis convexis flavidulis, valvd inferiore pallidiori ; long. 1,9, ; 
lat. 14; poll. 
Obs. Auribus inequalibus. 
Habitat in freto Magellanico passim. Mus. nost. 
This shell is found attached to the leaves of the Fueus giganteus, 
and, with other Mollusca, is the food of the Steamer or Race-horse 
Duck ( Micropterus brachyptera and M. Patachonica). 
