ART. 22 MIOCENE GASTROPODS AND SCAPHOPODS MANSFIELD 25 



the Gurabo formation, Dominican Republic. Unfortunately the 

 specimen is too corroded for exact specific comparison. 



Genus MANGILIA Risso 



MANGILIA MTCROPLEURA Guppy 



Plate 3, fig. 7 



Mangelia micropleura Guppy, Sci. Assoc. Trinidad Proc, p. 171, 1867 (de- 

 scribed) ; Geol. Mag. London, new ser., decade 2, vol. 1, p. 410, pi. 18, 

 fig. 6, 1874. 



The following is Guppy 's original description of this species : 



" Subfusiform, longitudinally ribbed, the ribs crossed by numerous 

 striae, of which a prominent one forms an angle on the upper part 

 of the whorls; last whorl longer than the spire; aperture rather nar- 

 row, lanceolate, with a sinus on the posterior part of the thickened 

 peristome." 



" Pliocene, Matura. Allied to 31. pidcheUa. The ribs vary con- 

 siderably as to size and distance apart. It was denominated M. taen- 

 iata in my list of 1864." [Unable to find it in this list.] 



Redescribed : 



There are in the United States National Museum (Cat. No. 

 115583) six specimens labeled Mangelia micropleura Guppy (types). 

 Matura, Trinidad (Guppy), all of which bear the same specific char- 

 acterization. The shell is subfusiform, rather stout, solid, strongly 

 axially sculj)tured and possesses about two nuclear and four post- 

 nucle'ar whorls. Nuclear whorls are strongly inflated; the second 

 one is sculptured with many threadlike, intrasutural axials and a 

 fine, anterior medial, spiral thread. Postnuclear spire whorls with 

 a central, angled periphery ; suture narrowly and sh'allowly grooved. 

 Axial sculpture consists of about nine, strong, slightly arcuate, sharp, 

 intrasutural ribs, intercalated by rounded valleys wider than the 

 ribs. Spirally sculptured with a strong inti-'a-axial cord at the 

 periphery of the whorl and by about two smaller equall}^ spaced 

 cords between the peripheral cord and the" anterior suture. Body 

 whorl longer than spire, sculptured axially with strong ribs extend- 

 ing along the canal into the siphonal fasciole; spii-'ally sculptured 

 with 10 to 12 low cords, widely spaced over the slope and prominent 

 and closely spaced over the siphonal fasciole. Aperture uniformly 

 rather narrow. Outer lip sharp with a strong varix behind and near 

 the margin. Anal sinus deep, wide, rounded, obliquely placed and 

 situated near the suture. Anterior canal short and wide. 



Dimensions : Largest specimen : Altitude 6 mm. ; greatest diameter 

 2.5 mm. ; length of aperture 2.5 mm. 



This species is similar to Mangilia plicosa C. B. Adams, 'a species 

 reported from the Pliocene to the Recent. 



