C R E P I D U L A . 



Plate I. 



Genus CREPIDULA, Lamarck. 



Testa ovaia vel ohlonga, plerunujue obliqua, extus laviffuta, 

 raru costata, apice brni, sapiss'mif marffiiiali, phis 

 minus rostrnto, i/ifits cava, lamina //ori:oniali septi- 

 formi, inlerdmn ad latus emaryhiald. 



Shell ovate or oblong, gi-adually oblique, smooth exteriorly, 

 rarely ribbed, with the apex mostly marginal and 

 more or less beaked, interiorly hollow, with a hori- 

 zontal septum-like lamina, sometimes notched at the 

 side. 



The Crepidula, or true Slipper Limpets, are character- 

 ized by the internal appendage, which is the distinguishing 

 feature of this family, assuming a horizontal deck-like form. 

 The species have been little added to since they were mo- 

 nographed twenty-five years ago by Mr. Broderip, and 

 several then described as new have proved to be varieties 

 of others. They are chiefly inhabitants of the New 

 World. 



Species 1. (Mus. Cuming.) 



Crepidula ungdiformis. Crcp. testa ovali vel ohlongd, 

 plana aid concavd, srepe contortd, complanatd, extus 

 concentrice striata, epidermide subpilosdjiavescenle in- 

 terdura versus marginem indutd, inttis nitente-albd ; 

 appendicc siibampliter septiformi, ad latus suhemargi- 

 nald. 



The nail-shaped Crepidula. Shell oval or oblong, 

 flat or concave, often twisted, smooth, externally con- 

 centrically striated, sometimes covered towards the 

 margin with a yellowish somewhat hairy epidermis, 

 internally shining-white ; appendage rather largely 

 septum-shaped, slightly notched at the side. 



Lamahck, Anim. sans vert. vol. vii. p. 642. 



Patella crepidula, LinnsBUS. 



Crepidula calceoiina, Desliayes. 

 Crepidula sinuosa, Turton. 

 Crepidula Candida, Risso. 

 Crepidula Italica, Defrance. 

 Crepidula plana. Say. 



Hab. Mediterranean and Atlantic sens. 



Extremely variable in form, according to its place of at- 

 tachment, but uniformly of a thin, white, brittle substance, 

 shining and subdiaphauous on the inner side, while the 



outer is frequently covered towards the margin with 

 yellowish somewhat hairy epidermis. 



Species 2. (Fig. a, 6, Mus. Taylor.) 



Crepidula porcellana. Crep. testa ovatd, conccxu, 

 solidiusculd, apice recurvd et subrostratd, albidd, intus 

 extusque Uvido-rufo et purpurea tinctd et radiatim ma- 

 cidatd ; appendice interna subprofiindd, concavd, medio 

 siunatd. 



The porcelain Crepidula. Shell ovate, convex, rather 

 solid, recurved and slightly beaked at the apex, whit- 

 ish, stained and radiately spotted within and without 

 with livid-red and purple ; internal appendage rather 

 deep, concave, sinuated in the middle. 



Lamar{ K, Anim. sans vert. vol. vii. p. 642. 

 Fati-lla porcellana, Linnaeus. 



Eab. West Africa. 



Mr. Cuming possesses small specimens of this species 



from West Africa, but there is every reason to believe that 



it has a far wider range of habitation. 



Species 3. (Fig. a, h, Mus. Cuming.) 



Crepidula dilatata. Crep. testa ovato-rotundatd, cras- 

 siu.iculd, siibirrfyidari, oblique curvatd, intus extusque 

 albidd, lirido-fiisro ad marginem tinctd et radiatim ti- 

 nea td ; appendice inter nd roncavitisculd, rotunda td, ad 

 latus profundi einarginatd. 



The dilated Crepidula. Shell ovately rounded, rather 

 thick, somewhat irregular, curved obliquely, whitish 

 within and without, stained and radiately lineated at 

 the margin with livid-brown ; internal appendage ra- 

 ther concave, rounded, deeply notched at the side. 



Lamarck, Anim. sans vert. vol. vii. p. 644. 



Hab. Straits of Magelhaens and Falkland Islands. Cliili ; 

 Cuming. 

 This fine species may be chiefly recognized by its 



obUquely curved concave form, and livid-brown marginal 



colouring. It is common of a smaller size. 



Species 4. (Fig. a, b, Mus. Ci 



Crepidula excavata. Crep. testa ohlongo-ovafd, cras- 

 siuscidd, stiblurtiiosd, lideralder coinpressd, apice obli- 



