k 



MAZATLAN UNIVALVES 359 



Gentts ALVANIA, Risso. 



In tliis section are deposited certain turrited E,issoida3, with 

 tumid -whirls. They do not however correspond with the genus 

 as defined by S. ^ A. Ad. Gen. vol. i. p. 330. 



Cingula, pars, C J5. Adams. 



412. PAlvania excuevata, n. s. 



?A. t. tenui, turritd, elongata, purpwreo-fuscd, pupafarmi, 

 onarginihus spirce excurvatis ; anfr. viii. quorum ii. primi pur- 

 purei, IcBves, apice planato ; dein iii. tumidiores, bi- seu tri-cari' 

 nati ; reliqui suhplanati, sculptiird minus expressd ; superficie 

 valde irregitlariter cancellatd ; costis ohtusis, scepe ohsoletis, 

 circiter XX., ad pen'phenam evanidis ; liris spiralibus quarum 

 plerumque iii. spird monstrantur, circa basin (injuniore inter- 

 dum Icevem) subangulatam circiter iii. ; interstitiis liaud impres- 

 sis, nunc liris mine costis siiperantibus ; aperturd subovali, 

 subquadratd ; labro tenui ; labia tenuissimo, rimulam umhilica- 

 lem vix monsfrante. 



This shell, in its regular growth and markings, reminds us 

 of Turritella goniostoma. About 100 specimens were found, 

 but most of them were extremely imperfect. Long. "112, 

 long. spir. '077, lat. '038, div. 25". 



Sab. — Mazatlan ; rare, off Chama and Spondylus ; L'pool Col. 

 Tablet 1709 contains 8 sp. varying in age, colour and sculp- 

 ture. In one the sculptured layer is entirely removed, and the 

 shell is only known by its shape. 



413. Alvania effusa, n. s. 



A. t. "A. excurvatce" simiU, sed solidiore, apice acutiore, 

 spira regulari, anfr. tumentibus, normaliter cancellatis ; costis 

 circiter xx. cvtantibus, ad basin evanidis, a liris spiralibus 

 circiter sMi. tuberculatis ; interstitiis et suturis valde impressis ; 

 basi effusd, striulis paucis axin solidam versus ; aperturd 

 oblongd ; labro solido, interdum varicoso ; labio inconspicuo ; 

 umbilico nullo. 



Only one specimen was found of this beautiful species, which 

 is distinguished from A. tumida by its very elongated shape, 

 and from A. excurvata by the above characters. In sculpture 

 it resembles Phos. Lo)ig. 'US, long. spir. 'Q(J1, lat. '042, div. 22". 

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



Tablet 1710 coutaiua the specimen. 



