Crepidula.] GASTROPODA. 287 



Dentition. Hutton, T.N.Z.I., xv, 122, pi. 14, f. B ; xvi, 214 : 

 Gray, Guide Moll. B.M., 115. 



Hab. Throughout New Zealand, from low -water mark to about 

 40 fathoms. The species is cosmopolitan. 



Remarks. The C. crepidula, L., and monoxyla, Less., were hitherto 

 considered to be distinct species. Pritchard and Gatliff, however, 

 united them under C. unguiformis, Lam. The dentition of the two 

 does not show any marked difference, and the protoconch as well as 

 the nepionic shells show the same characters. The shells are mostly 

 found upon Turbo smaragdus, and in the mouth of Siphonalia, &c. 



Fossil. Miocene and Pliocene. 



2. Crepidula costata, Sowerby, 1824. Plate 44, figs. 6, 6a. 



Crepidula costata, Sow., Gen. of Recent & Foss. Shells, No. 23, f. 3. Patella 

 aculeata, Graelin, Syst. Nat., ed. xiii, 3693. C. costata, Sow., Voy. 

 Astrol., iii, 1835, 414, pi. 72, f. 10-12. C. nfuleata, Gmel., Man. 

 Conch. (1), viii. 129, pi. 39, f. 61-65: Chall. Rep., xv, 458. 



Shell oval, moderately convex, solid, radiately strongly ridged. 

 Sculpture consisting of strong radiating nodulose or spinose ridges, 

 often interrupted by periods of rest ; interstices with more or less 

 numerous radiate strise ; growth-lines prominent, and lamellar on 

 the anterior part of the shell. Colour whitish, yellowish, or brownish, 

 often chestnut-rayed ; interior often blotched or rayed with brown 

 or purple ; basal plate white. Epidermis very thin, horny, deci- 

 duous. Protoconch minute, oblique, of 1 smooth and flatly convex 

 Avhorl, mostly with a few brown lines ; the nepionic shell has very fine 

 concentric growth-lines, but no radiate sculpture. The shell is flatly 

 to highly convex, with the apex lateral, posterior, and terminal. In- 

 terior porcellanous, polished, the margin of the roof more or less 

 denticulate. Basal plate flat or convex, free margin sharp, almost 

 straight ; length of the plate somewhat over one-third of the total 

 length of the shell. 



Length, 50 mm. ; breadth, 31 mm. ; height, 18 mm. (large specimen). 



Dentition. Hutton, T.N.Z.I., xv, 122, pi. 14, f. A. 



Type in the British Museum. 



Hab. North Island of New Zealand. Brought to England by 

 Captain Cook. 



Remarks. Sowerby's species was first figured, and his specific 

 name has to be adopted. This again is a cosmopolitan species. Gray 

 (P.Z.S., 1867, 737) mentions the following species as synonyms : C. 

 echinus and hystriz, Broderip ; C. californica, Nuttall. 



Fossil. Miocene and Pliocene. 



Fam. NATICIDJE, Swainson. 



Animal with small tentacles, which are lanceolate, wide apart, 

 connected by a veil ; eyes absent or placed under the skin, behind 

 the tentacles ; foot highly developed and provided with an aquiferous 



