414 MAZATLAN tTNIVALTEa 



transversis, valde extantihus, ad basin continuis ; interstitiis 

 subundulatis, IcBvibus ; aperturA elongatd, pei'itremati con- 

 finud, axi plica distinctd munitd. 



Nuclear part rerj small and sunken ; next wliirl -with 

 numerous, fine, ratiier undulating ribs ; wliich gradually be- 

 come less numerous, straight, sharp, and very prominent. 

 Whirls sharply angled at the shoulder, at rather less than 90*. 

 The lip is broken in both specimens, but it is distinctly con- 

 tinuous. There is a general resemblance in form, (though the 

 whirls are less numerous and longer) to Chemnitzia scalaris. 

 Long. •!, long. spir. "OeS, lat. "37, div. 20". 

 Hab. — Mazatlan ; 2 sp. off Chama ; L'pool Col. 



Tablet 1962 contains the finest specimen. 



498. Paethema qtjikqtjecincta, n. s. 



P. t. forma " P . scalariformi" simnlante ; sed vertice nucleoso 

 tumente, anfr. ii., verticaliter sitis ; anfractibus iii. et dimidio 

 planatis, aqiialiter transversim clathratis ; clathris acutis cir- 

 citer xiii. ad suturam antice declivihus, postice muricatis ; 

 suturis acute exaratis ; lirulis \. spiralibus cinctd, quarum una 

 suturam continuat, altera supra partem declivem, tres in basi 

 sitcB sunt ; aperturd ovali, peritremati continud, plied parvd, 

 declivi, intus celatd, hand umbilicatd. 



The first normal whirl of this beautiful shell is marked Kke 

 the rest. The ribs are more numerous than in P. scalariformis, 

 from which it is at once distinguished by the 5 spiral threads, 

 of which 3 appear on the base, one carries on the sutxire, and 

 the fifth is above it, bounding the slanting portion of the 

 whirls. Long. '063, long. spir. '038, lat. '025, div. 20". 

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



Tablet 1963 contains the finest specimen. 



499. Pabthenia lacunata, n. s. 



P. t. ovali, minimd, albd, tenui, subdiaphand ; vertice 

 nucleoso marginibus spirce subexcurvatis nequaquam superante, 

 decliviter siio, rotundato, vix tumente, apice celato ; anfr.m. 

 normalibus clathris circiter^ixm. solidis tranversis obtusis, munt- 

 tis ; peripheriam versus a lacund concavd, insculptd interruptis, 

 circa basin ad umbilicum minirnutn tenue continuis; lacund 

 carinis duabus spiralibus cinctd, quarum. una supra suturam, 

 una ad suturam sites sunt; interstitiis ad basin tenuissime 



