434 MAZATLAS TKIVALTES 



of the latter. It agrees with all the other sections of the 

 family in haviug its limits badly defined. "When the forms 

 from various seas are better known, the entire famUy will 

 need revision ; meanwhile, for convenience' sake, these species 

 are separated with a name in remembrance of Prof. W. Dunker, 

 the learned author of Ind. Moll. Guin., Moiioc/r. Mytil. &c. 



536. DUXKEEIA PATJCILIEATA, 71. S. 



D. t. turi'itd, soUdiore, alba ; vertice nucleoso haud producto, 

 marginihus spirce recfis liaud superante ; anfr. rotu7idatis, 

 postice suhangulatis, suturisprofimdis, liriilis acutis circiter xiv. 

 interstltiis latis, undatis, spiraliter tenuissime striatis ; aper- 

 turd elongatd, subquadratd. 



This species somewhat resembles Parthenia scalariformis, 

 but is entirely destitute of the columellar plait. The last 

 whirl has perished : the remaining six measui'e long. '083, 

 long. spir. '055, lat. "027, div. 15". 



Hab. — Mazatlan ; 1 sp. off Chama ; L'pool Col. 



Tablet 2007 contains the specimen. 



537. DuifKEEIA SUBANGULATA, n. S. 



D. t. subcylindricd, albd ; vert, ntccl. glohoso, valde declivi, vix 

 proiniiiente, anfr. ii., apice pcene celato, marginibus spirce sub- 

 excurvatis haud superante ; anfr. normalibus v. convexis, infra 

 suturam valde profundam vix angulatis ; lirulis tran^versis 

 tenuibus circiter xx., ad suturam inierdum continuis, ad basin 

 evanidis, a striis spiralibus, parum elevatis, in anfr. penult, iv. 

 eleganter cancellatis, interstitiis quadratis ; striis circa basin 

 rotundafam tnagis extantibus, tenuissime in lineis lirularum 

 cancellatis ; upcrturd subovali. 



Variat, t. minore, liris exilioribus, crebrioribus. 



The outline of this elegantly cancellated species, when 

 young, resembles D. paucilirata : it is then however much 

 broader and more augulatcd, Avith more numerous ribs, and a 

 scarcely twisted columella. In the adult state the lirulse, which 

 cease at the suture, arc continued round the base, in the form 

 of minute lines decussating the spiral strijE, as these decussate 

 the ribs above. A very young sp. with two normal whirls 

 measures "032 by "023. The largest in the L'pool Col. with 

 four normal whirls, measures long. "007, long. spir. '045, 



