ART. 22 MIOCENE GASTROPODS AND SCAPHOPODS MANSFIELD 21 



Dimensions: Type (U. S. Nat. Miis. Cat. No. 352634) measures: 

 Altitude 34 mm. ; greatest diameter 9 mm. 



This new species resembles in a general way Drillia fusiforviis 

 (Gabb) from the Gurabo formation, Dominican Republic, Imt dif- 

 fers from that species in possessing fewer axial ribs, a less con- 

 stricted suture, a narrower aperture, and a smooth interior outer lip. 



A very closely related form to the new species occurs at station 

 8519, Dominican Republic, a horizon referred to the Gurabo 

 formation. 



The Recent analogue appears to be DrlUa gnindlacM Dall and 

 Simpson from Majaguez Harbor, Porto Rico. 



Occurrence. — Middle or lower Miocene : Guaico-Tamana Road, 

 2 chains east of mile 13 from junction with Eastern Main Road, 

 Trinidad, British West Indies. 



DRILLIA. species, aflf. D. FUSIFORMIS (Gabb) 



Several young and fragmental adult specimens from stations 9212 

 and 9219 apparently belong to the group of BriUa fusiformis 

 (Gabb), but these are considered inadequate for definite specific 

 comparison. 



DRILLIA INNIADDA, new species 



Plate 3, figs. 4, 9 



Shell small, stout, semiporcellaneous, strongl}- axially sculptured 

 and consists on the larger cotype of four slightly inflated whorls, 

 the nucleus and early whorls broken off, and on the smaller cotype 

 of one and one-half nuclear and six postnuclear whorls. Suture dis- 

 tinct, grooved, not appressed. Nucleus rather small, apical whorl 

 minute ; whorls smooth and rounded. Postnuclear wdiorls sculptured 

 with about ten, strong, arcuate, triangular, sharp-edged ribs, sepa- 

 rated by narrow grooved interspaces. At the base of the last whorl, 

 the ribs diminish in size and are replaced on the canal by small, 

 rounded, crowded growth lines which twist dextrally and overrun the 

 lower part of the pillar. In addition to the axials, there are many, 

 close-set, irregular, microscopic growth lines overrunning the sides of 

 the axils and interspaces. Spiral sculpture is very obscure, consist- 

 ing only of a narrow subsutural band and a faint interaxial stria on 

 the posterior third of the whorl. Aperture rather wide. Anal sulcus 

 apparently wide and situated near the suture. Margin of inner lip 

 erect and partly overlaps the pillar. Canal rather short and slightly 

 twisted. 



Dimensions: Cotypes (U. S. Nat. Mus. Cat. No. 352635) meas- 

 ure: (Larger cotype) altitude 9 mm.; greatest diameter 3.3 mm.; 

 (smaller cotype) altitude 6 mm.; greatest diameter 2.1 nnn. 



