DIAGNOSES 

 OF 



NEW FORMS OF MOLLUSCS 



COLLECTED BY COL. E. JEWETT 



ON 



THE WEST TROPICAL SHORES OF NORTH AMERICA; 



BY 



PHILIP P. CARPENTER, B.A., Pn.D. 



Rissoina expansa* 



R. testa magna, lata, tenuisculpta, alba, nitente, subdiaphana; 

 marginibus spirae parum excurvatis ; anfr. nucl. Isevibus, vertice 

 mamillato ; norm, v., planatis, suturis distinctis ; costulis radianti- 

 bus circ. xxiv., obtusis, baud extantibus, interstitia sequantibus, 

 peripheriam versus evanidis ; circa basim productam striis spirali- 

 bus expressis ; medio laevi ; apertura valde expansa, semilunata ; 

 labro subantice producto, varicoso, antice et postice alte sinuato ; 

 labio calloso. Long. '35, long. spir. '18, lat, '17 poll., div. 30. 



Hab. Mazatlan (teste Jewett]. 



This fine species is the largest known in the fauna. It most 

 resembles R. infrequens, C. B. Ad., which was described from a 

 dead shell. 



Mangelia hamata. 



M. testa carneo-aurantiaca, satis turrita, margjnibus spirse excurvatis 5 

 anfr. nucl. ii. globosis, tenuissime cancellatis, apice mamillato ; norm, 

 vi . , subelongatis, in spira tumentibus, subangulatis, suturis impressis ; 

 costis radiantibus x.-xii., acutioribus, validis, circa basim pro- 

 longatam continuis ; interstitiis concavis ; lirulis spiralibus filosis, 

 distantibus, supra costas transeuntibus, in spira iii.-iv. ; apertura 

 subelongata, quasi hamata, intus Isevi, intense colorata: iabro 



293 



