414 HAZATLAN^ UNI VALVES 



transversis, valde extanlibus, ad basin continues ; interstitiis 

 subundulatis, l&vibus ; aperturd elongatd, peritremati con- 

 tinud, axi plied distinctd munitd. 



Nuclear part very small and sunken ; next whirl with 

 numerous, fine, rather undulating ribs ; which 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. '1, long. spir. '065, lat. '37, div. 20. 

 Hob. Mazatlan ; 2 sp. off Chama ; L'pool Col. 



Tablet 1962 contains the finest specimen. 



498. PAETHENIA QUINQTJECINCTA, n. s. 



P. t. forma "JP. scalar if or mi" simulante ; sed vertice nucleoso 

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

 planatis, cequaliter transversim clathratis ; clathris acutis cir- 

 citer xiii. ad suturam antice declivibus, postice muricatis , 

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

 suturam continuat, altera supra partem declivem, tres in basi 

 sitce sunt ; apertura ovali, peritremati continud, plica parvd, 

 declivi, intus celatd, Jtaud umbilicatd. 



The first normal whirl of this beautiful shell is marked like 

 the rest. The ril^g 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 suture, and 

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

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

 Hab. Mazatlan ; 2 sp. off Spondylus ; L'pool Col. 



Tablet 1963 contains the finest specimen. 



499. PABTHENIA LACUNATA, n. s. 



P. t. ovali, minima, alba, tenui, subdiapJiand ; vertice 

 nucleoso marginibus spires subexcurvatis nequaquam superante, 

 decliviter sito, rotundato, vix tumente, apice celato ; anfr. iii. 

 normalibus clathris circiter~&.v\i\. solidis tranversis obtusis, muni* 

 tis ; peripJieriam versus a lacuna concavd, insculptd interruptis, 

 circa basin ad umbilicum minimum tenue continuis ; lacund 

 carinis duabus spiralifius cincta, quarum una supra suturam, 

 una ad suturam sitce sunt; interstitiis ad basin tenuissime 



