390 MAZATLAN UNIVALVES 



p. 181, but Hinds points out differences, Thes. Conch, p. 184. 

 Lo7ig. "5, long. spir. '32, lat. "16, div. 30°. 



Sab. — Acapulco, Sonsonati ; Mus. Cuming. — Xipixapi, Cum- 

 ing. — Mazatlan ; extemely rare ; L'pool Col. 



Tablet 1878 contains 1 specimen, presented by R. D. Darbi- 

 shire, Esq. 



Family PLEUEOTO:Vin)^. 



All tbe young Pleurotomidse examined bave tke apex normal, 

 with about three -whirls smooth and subtransparent. The 

 opercula in this Suborder, as in Proboscidifera, are very fre- 

 quently repaired after fractiu-e.* Whatever be their normal 

 condition, they always reconstruct from a central nucleus : a 

 circumstance which seems to shew that the variations in oper- 

 cula are not of so much importance as in the shells ; the latter 

 being almost always repaired after the normal pattern. 



Ge^-us PLEITEOTOMA, Lain. 



Journ. Hist. Nat. 1799, pars : canal elongated, operculum 

 subtriangular, nucleus at the anterior extremity. 



Turris, (Humph.) Gray, P-roc. Zooh Soc. 1847, p. 134.— 

 H. Sf Ad. Gen. vol. i. p. 87. (Non Montf.) 



457. Pleueotoma funiculata, Val. 



Kien. Icon. Conch, p. 24, no. 18, pi. 16, f. 1. — Jive. Conch. Ic. 



pi. 11, sp. 95. 

 = P. olivacea, var. Rve. loc. cit. (a prim, man.) pi. 4, sp. 27; 



non Soto. Proc. Zool. Soc. 1833, p. 136. 

 Surcula (Turris) funiculata, H. Sf A. Ad. Gen. i. 88. 



The aspect of the Mazatlan shells is intermediate between 

 the figures of Kien. and Eve. They differ from the figure of 

 P. olivacea in the widely excavated space of the posterior sinus, 

 and in the keeling of the whirls below it. The epidermis in 

 the young shells is ashy, in the adult of a rich glossy olive. 

 There are numerous coarse spiral strise, two of which appear 

 above the suture. There are about 10 nearly obsolete costae, 

 rising into tubei-clcs at the periphery. Nuclear whirls smooth. 



• T. Qray on Beproduction of Opercula, Ann. Nat. Sist. 1851, p. 419. 



