366 F. B. Cowjjer Reed — New Fossils from Haverfordwest. 



ribs parallel to the keel, but become sinuous, broken, and irregular 

 near the mouth. The shells are mostly crushed, but must have 

 reached a rather large size, some measuring 50-70 mm. across the 

 mouth. The true position and affinities of this form are doubtful. 



Bkllerophon (Bucanopsis) secundus, sp. nov. (PI. XX, 

 Figs. 15, 15a.) 



Shell subglobose, with broad, rounded back ; of few volutions ; 

 whorls transversely subquadrate in section, broader than high ; 

 umbilicus moderately large, deep, with subangular margins, 

 exposing inner whorls ; aperture transverse, more or less expanded ; 

 inner lip reflexed on inner end of last whorl ; band rather broad, 

 with narrow, raised margins, not depressed, with fine, gently curved 

 lunulse; surface of shell on each side of band marked with rather 

 strong, regular, straight, parallel, subequal, revolving raised lines, 

 about 24 in number, closely crowded near band, but becoming 

 more widely separated laterally, crossed at right angles by very fine, 

 transverse, slightly wavy striae. 



Dimensions. — Height about 15 mm. 



Horizon. — Eedhill Beds. 



Localities. — Prendergast Place and Lane. 



Bemarhs. — The true generic position of this species in Ulrich's 

 classification seems to be in £ucanopsis.^ But our specimens are 

 so crushed and distorted that it is upon the characters of the 

 ornamentation and slit-band that we must chiefly depend ; and these 

 are sufficiently definite and important to mark the species. 



The term Bncania is employed by Ulrich in a much more 

 restricted generic sense than Hall originally intended, and than later 

 authors (Waagen, Koken, etc.) have used it, and some of the species 

 now placed in Bucanopsis have been included in it by them. Ulrich 

 points out that in Bucanopsis the spiral surface - markings are 

 straight and parallel with the direction of the whorls, while in 

 Bncania sens. str. they are wrinkled, interrupted, and more or less 

 oblique in direction. He would provisionally include in Bucanopsis 

 all the Palseozoic spirally striated shells which agree in other 

 respects with Bellerophon. The type is B. carinifera, Ulrich, from 

 the Trenton Group.^ The full definition of the genus is as follows : 

 " Shells agreeing in all respects with Bellerophon, excepting that 

 their surfaces are cancellated by regular, revolving, and transverse 

 strise. The volutions enlarge rapidly, giving a broadly expanded 

 aperture ; the umbilicus is of moderate size, and may be closed 

 entirely, while the inner lip is always somewhat thickened. The 

 revolving lines are never oblique nor wrinkled." 



Our Eedhill species may be compared with the type species, 

 which is the only Ordovician form previously known ; but the band 

 appears to be less prominent and the back broader, and the spiral 

 lineation slightly difierent. 



1 Ulrich: op. cit., pp. 853, 922. 



2 Ulrich: op. cit., p. 925, pi. Ixii, figs, 56-61. 



