240 ** MAZATLAN UNIVALVES 



J 298. VlTRINELLA MONILE, n. S. 



V. t. subelevatd, kelicoided, diapkand, alba ; anfr. iv. et 

 dimidio, convexis, quaruin tres primi laves seu spiraliter sub- 

 striati sunt, subito in superficlem minutissime decussatam mutan- 

 tes ; liris quoad xx. spiralibus, transversim decus satis, interstitiis 

 subovalibus seu subquadratis ; apertura spatiosd, peritremati 

 continue, parum ab anfr. penult, impresso, labro ut in lanthina 

 sinuato ; umbilico anfractus intus vix monstrante, regione um- 

 bilicali valde incurvatd. 



This species is intermediate in form between V. decussata 

 and V. monilifera. The decussating structure, which covers 

 the surface and enters the umbilicus, is extremely fine ; the 

 suboval punctures (in a favourable light) appearing like rows 

 of pearl necklaces. The adult portion rarely extends to a whirl 

 and a half. Nearly 30 specimens were found, more or less 

 perfect ; of which the smallest is '023 across ; the largest 

 measures long. '035, lat. '055, by '045, div. about 125. 



Hab. Mazatlan ; very rare, off Chamge and Spondyli : L'pool 

 Col. 



Tablet 1149 contains 1 imperfect, and 3 perfect specimens of 

 different ages. In one, the spiral lines suddenly become more 

 numerous. 



299. YlTEINELLA MONILIFERA, n. S. 



V.t. "V.monili" soulpturd et indole simili, sed discoided, 

 anfractibus subplanatis, decussatione tenuiore, umbilico maximo, 

 anfractus ad apicem monstrante ; apertura vix continua, sin- 

 uatd. 



This species might without impropriety be ranked with 

 Cyclostrema ; the apical portion however is as in Vitrinella. 

 The mouth is scarcely altered in form by the penultimate 

 whirl, and is sinuated as in Adeorbis. The necklace pattern is 

 rather finer than in V. monile. Long. '015* lat. '04 by '035. 

 Div. about 175. 



Hob. Mazatlan ; 7 specimens in Chama and Spondylus ; 

 L'pool Col. 



Tablet 1150 contains the largest and the most characteristic 

 gpecimen. 



