Maryland Geological Survey 463 



? Pyrifusus (immature) 

 Plate XVI, Fig. 4 



Description. — Shell very small, fusiform, whorls probably about six in 

 number, those of the spire feebly convex, the body whorl quite strongly 

 so ; maximum diameter not far from the median horizontal ; axial sculp- 

 ture of sharply rounded riblets, broader and more obtuse upon the body, 

 eighteen in number on the later whorls ; spirals cordate in character, four 

 in number on the penultima, with possibly a secondary upon the obscure 

 shoulder; somewhat nodulated at the intersections with the axials, the 

 interareas between the spirals and axials forming a series of squarish pits ; 

 spirals upon the body less regular in character than upon the spire ; pri- 

 maries ten upon the body, excluding the pillar, more distantly spaced upon 

 the periphery, rather lower and more obtuse than upon the spire and with 

 regularly intercalated secondaries; pillar threaded with nine to twelve 

 subequal lirse which become increasingly more crowded toward the ante- 

 rior extremity ; characters of aperture not known. 



Type Locality. — Two miles southwest of Oxon Hill, on Mrs. Linton's 

 farm. 



Occurrence. — Monmouth Formation. Two miles southwest of Oxon 

 Hill, Prince George's County. 



Collection. — Maryland Geological Survey. 



Family BUCCINIDAE 



Subfamily CHRYSODOMINAE 



Genus EXILIA Conrad 



[Jour. Acad. Nat. Sci., Phila., 2d ser., vol. iv, 1860, p. 291] 



Type. — Exilia pergracilis Conrad. 



Shell fusoid in outline, much attenuated, multispiral, external sculpture 

 delicate, the costals numerous and slightly arcuate, the spiral threading 

 fine and crowded; aperture narrow, produced anteriorly into a long 

 straight canal; outer lip sharp and simple; columella non-plicate. 



The genus has formerly been considered in its American distribution to 

 be restricted to the Eocene. 



Etymology: A corruption of exilis, slender. 



