262 MAZATLAN UNIVALVES 



which covers the umbilicus, leaving only a slight chink. A 

 second sp. agrees in all respects except that the spiral sculp- 

 ture is coarse and somewhat moniliform ; but it is too much 

 weathered to decide on its affinities with confidence. Long. "019, 

 lat. -039 by '034, div. 153". 



Sah. — Mazatlan ; 2 sp. off Chama and Spondj'lus ; L' pool Col. 



Tablet 1170 contains the typical specimen. 



320. Ethalia pallidtjla, ?j. s. 



E. t. glohosd, solicla, alba ; ad spiram planaid, ad hasim pro- 

 ductd ; anfractihiis m.., suturd indistiiictd, apice planatd ; totd 

 swperjicie striis spiralibus suhrugulosis impressd ; callositate 

 ■minimd ; umhilico nullo ; aperturd elongatd, ad hasim sub- 

 angulatd ; labro aciUiore, labio conspicuo. 



A little globular shell, produced at the base of the columella, 

 and presenting the general aspect of the yoimg of Lacima 

 paUidula. It is on the extreme verge of the genus, the com- 

 pact spire preventing the development of the callus. Long. '029, 

 lat. -044 by -035, div. 170". 



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



Tablet 1171 contains the specimen. 



321. Ethalia caeinata, n. s. 



E. t. discoidali, planatd, aurantio-fuscd ; anfractibus iv. et 

 dimidio, quarum iii. primi Iceves, vix amplectentibus. suturd 

 valde impressd ; sub peripheriam acute carinatd ; totd super- 

 Jicie rugulis incrementi confertissimis omatd ; regione umbilicali 

 coiicavd ; callositate spirali elongatd, angustd, rimam cojufpicu- 

 am umhilicalem gijrante,juxta labium parum planatd ; aperturd 

 subquadratd, sinuatd, a carina angulatd ; labio ad parietem 

 nullo ; labro intus suturam parum calloso. 



This charming little shell has the general aspect of Planorbis 

 carinatus, but -n ith the whirls a very little elevated, and the 

 keel just below the centre. The whirls very slightly embrace, 

 but are cemented by the long, thin callus. Both above and 

 below, it is covered with extremely close, nigulous, radiating 

 striuljE. In its mode of growth it affords a transition to Teino- 

 stoma. Long. 013, lat. "038 by "033, div. 175". 



LLab. — Mazatlan ; 2 sp. off Spondylus ; L'pool Col. 



Tablet 1172 contains the freshest (but smallest) specimen. 



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