from the West Tropical Shores of North America. 399 



Siphonalia fuscotincta, 



S. testa minima, turrita, albida, apicem versus fusco tincta ; anfr. 

 nucl. ii., compactis, subplanatis, apice mamillato ; norm, iv., con- 

 vexis, suturis impressis ; costis radiantibus rotundatis, tumentibus, 

 basim versus evanidis, interstitiis undulatis, subsequantibus ; lirulis 

 crebris spiralibus, costas superantibus ; apertura pyriformi, in 

 canalem brevem apertum contortum producta ; labro acuto ; la- 

 bio baud conspicuo ; columella canalem versus valde contorta. 

 ' Long. -17, long. spir. -1, lat. '08, div. 32°. 



Hab. Sta. Barbara (/<?zi?e//). 



The unique specimen is like a minute edition of Siphonalia 

 Kellettiiy but does not accord with the young of that or of any 

 other species known in the region. It is probably not mature. 



XLI. — Diagnoses of new Forms of Mollusca collected by Col. E. 

 Jewett on the West Tropical Shores of North America. By 

 Philip P. Carpenter, B.A._, Ph.D. 



Rissoina expansa. 



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

 marginibus spirse parum excurvatis ; anfr. nucl. laevibus, 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. 'S-o, 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. infreqiiens, C. B. Ad., which was described from a 

 dead shell. 



Mangelia hamata. 



M. testa carneo-aurantiaca, satis turrita, marginibus spiree excurvatis ; 

 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 ; labro 

 acuto, dorsalii.er varicoso, postice valde sinuato. Long. '2A, long, 

 spir. -13, lat. "1, div. 25^ 



Hab. Panama (teste Jewett). 



This very beautiful species is easily recognized by the varicose 

 lip, sloping off to a sharp edge; by the deeply cut posterior 

 notch, giving the smooth mouth a hooked appearance; by the 



