356 MAZATLAN TNITALVES 



407. PisAPis , sp. ind. 



Tablet 1703 contains a fragment of a species resembling 

 I. OToidea, but with very numerous fine spiral ribs, with broad 

 concave interstices, crossed by transverse ridges most develop- 

 ed on the penultimate whirl. 



Sab. — Mazatlan : 1 sp. on Spondylus ; L'pool Col. 



Family EISSOID^. 



Genus EISSO^A, D'Orb. 



Yoy. Am. Mer. 1810, p. 395.— P/i/Z. Sandh. Conch, p. 172.= 

 H. Sf A. Ad. Gen. vol. i. p. 327. — Base slightly channeled, 

 labrum thickened, operculum neritoid. 



Eissoa, pars, auct. 



408, EissoiXA STBiCTA, 3Il-e. 



R. t. alba, subturritd, solida, anfractihus ?x., apice 1 ,- 



lahro incrassato, ad mediam partem producto ; labia parvo, 

 reflexo ; columella trtincata ; costis radiantibits subrotundatis, 

 in anfractn uiroque circiter xx., striulis spiraUbus obsoletis ; 

 sutura impressd, costis ad apicem continuis. 



Eissoa stricta, Ml-e. in Zeit.f. Mai. 1850, p. 177, no. 37. 

 Comp. Eissoa fortis, C. B. Ad. Pan. Shells, pp. 178, 314, no. 245. 

 Comp. Eissoina pyramidata, A. Ad. 



A single specimen of this shell was found by Mr. Hanley in 

 the Spondylus washings. Menke's shell is still larger, measur- 

 ing 3'7 by 1' lines. Even Mr. Hanley's specimen is very 

 much larger than E. Woodwardii, which in general form it 

 much resembles, measuring long. *27, long. spir. (apice carente) 

 •17, lat. -11, div. 20". 



Sab. — ^lazatlan ; extremely rare ; Havre Col. 



Tablet 1704 contains some fragments which seem to belong 

 to this species, with an apex resembling that of E. Woodwardii, 

 but larger in proportion ; and a sketch of the unique sheU in 

 Mr. Hauley's Collection. 



