128 CREPIDULA. 



G. grandis, Midd. (fig. 33), G. minuta, Midd. (fig. 42), and G. 

 nummaria^ Gould (fig. 34), the latter from the interior of shells, 

 hence flattened. It appears to me that nummaria might as well 

 be referred to G. Lessoni as here, and that G. explanata, which 

 is placed in the sjmonymy of G. Lessoni, could also be equally 

 well placed here ; farther, these flat, interior-growing specimens 

 of Crepidula from the West Coast have about as much right to 

 a distinctive place as has G. unguiformis. 



C. MONOXYLA, Lesson. PI. 37, figs. 35, 36. 



Whitish, elongated, contorted, high-convex. 



Length, l-25-r5 inches. New Zealand. 



This species does not appear to have any special character- 

 istics ; a G. unguiformis growing on the outside of a narrow 

 shell would be apt to take on the same form. G. contorta, Quoy 

 (figured), and C. profunda, Button, are synonyms. 



C. ONYX, Sowb. PI. 37, figs. 37, 38; PI. 38, figs. 43-50; PI. 

 39, fig. 59. 



Eather thick, rugose, smooth or rarely radiately costellate, 

 chestnut or chocolate-colored within and without, sometimes 

 obscurely chestnut-rayed, the septum usually white. 



Length, 1*5-2 inches. Panama to Galifornia. 



Carpenter, in his Mazatlan Catalogue, endeavors to distin- 

 guish G. rugosa, Nuttall (fig. 37), from this species; the latter 

 having a shaggy epidermis, whilst that of rugosa, though some- 

 what lamellar, is glossy, never shaggy. The numerous speci- 

 mens before me, from many localities, do not seem to establish 

 this distinction, and probably the shaggy epidermis is the 

 result of rough water. I suspect that G. adunca, Sowb., with 

 its sharp elevated beak, although placed from this character in 

 a distinct section, will prove to be an onyx growing upon more 

 restricted surfaces. 



The synonymy will include G. hepatica (fig. 38), perhaps of 

 Deshayes, at any rate, of C. B. Adams ; but whether the G. 

 hepatica so identified by Krauss, or his var. complanata (fig. 45), 

 from the Cape of Good Hope, are identical, remains doubtful : 

 I can see no ditference, judging from the figures. G. immersa, 

 Angas (figs. 46, 47), from Australia, also appears the same. To 



