216 



ON THE TOrOGKAPHY AND GEOLOGY 



PLOCHEL^EA. Gabb, ii. gen. 



Shell oliva3-form, suture faint ; aperture linear deeply and obliquely notched at the base ; outer lip thickened in 

 the middle ; inner lip encrusted and bearing- several transverse folds of which the upper ones are smallest ; columella 

 strongly recurved at the base. ■ ' 



From its form and general apj3earance I feel inclined to consider this genns to 

 belong to tlie OUvidce although its details of character are strikingly like those of 

 Dihaphus. It seems to form in a manner a connecting link between the true Olives 

 and the genns Monoptygma of Lea (not of H. & A. xYdams).* 



I haVe before me specimens of Dihaphus edeiitulus and Mmiritia Barclayi, the 

 typical species of their respective genera. There is no possible room for doubt that 

 D. edentnlus is, at least sometimes, supplied with mitra-like folds. My specimen has 

 seven or eight and well-developed. Consequently Mauritia is synon3niious with 

 Dihaphus; and it seems to me that the genus should be placed i-ather with the 

 Mitras than with the Cones. The differences between the present genus and Di- 

 haphus are small, and it is possible that the two should be placed side l)y side, although 

 I strongly suspect that the resemblances are rather those of imitation than of true 

 relationship. 



p. c rassilab r um. Gabb, n. s. 



Shell elongate-oval, slightly tapering in advance in old specimens ; spire low, acuminate, whorls eight, suture 

 obsolete, its end, at the mouth, bent upwards ; body whorl rounded above, nearly straight on tlie sides. Aperture 

 linear, contracted in the middle by the encroachment of the outer lip, which is very much thickened in the middle ; 

 Inntr lij) encrusted, crossed by about eight slightly oblique folds, the most anterior of which are largest ; columella 

 strongly recurved, sinus deep and obli(^ue. Length about 1 inch. 



On one specimen are faint traces of the color })attei-n which seems to have been 

 small, more or less triangular light patches on a darker ground. 



This shell is unlike either D. edentula or Barclayi in its low spire, its olive-like 

 shape, in the end of the columella being bent directly backwards instead of laterally, 

 in the folds on the innei- lip being arranged in an order the reverse of that of 3fitjxi, 

 and ill the posterior elongation of the mouth, . 



FASCIOLARIA. Lam. ■ ' . • 



F. semistriata. Sby. Quait. .Jour. Vol. VI, p. 49. • ' ■ ' ' 



Id. Guppy, loc cit. Vol. XXII, p. 288, pi. 1(1, fig. 13. 



Differs from both i^^. tulipa and F. distans in being intermediate between them in 

 color pattern. It seems nearest to F. tulip)a in shape, but is more slender and has a 



* See Lea, Contributions to Geology. The genus Mo7ioptygma is described and figured by Mr. Lea as an olive 

 with a very large single fold on the middle of the columella. The author adds that he has received a littla shell from 

 the E ist Indies which he considers should be added to the genus. Authors of recent couchology have all assumed this 

 little shell as the type of the genus, ignoring alike the generic description and the excellent figures of the typical 

 species. H. & A. Adams have monographed the recent shells of this unnamed genus in the Proc. Zool. Society, 

 referring them incorrectly to Monoptyguia of Lea. 



