404 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Mar. 23,
Straparolus Wrightianus, nov. sp, (Pl. XXVI. fig. 23.)
Shell small, discoidal, plano-concave above, deeply but narrowly umbilicated below : whorls five, regularly rounded, slightly embracing, smooth.
The species is related to S. minutus, Schubler, from the " zone of Ammonites opalinus" but differs in its fewer and embracing whorls, giving it a more compact form, and in the absence of a keel.
Dimensions. Diameter 0.15 inch ; height 0.l inch.
Dedicated to my friend Dr. T. Wright, from whom I received the species, having been obtained by Mr. Brady in the residuum of washings for Foraminifera.
The species associated with S. Wrightianus are S. bellulus, nov. sp. ; S. aratus, nov. sp. ; Littorina biornata, nov. sp. ; Pecten acutiradiatus ; Dentalium minimum, Strickland; Leda Galatea, D'Orb; Waldheimia numismalis; a few Ammonites (A. Loscombi, juv., &c), &c.
Locality. Near Lyme Regis (zone of Am. Jamesoni).
Straparolus bellulus, nov. sp. (Pl. XXVI. fig. 22.)
Shell small, discoidal, plano-concave above, deeply but narrowly umbilicated below ; whorls five, regularly rounded, slightly embracing, marked by numerous longitudinal costulae and crossed by faint strongly arched lines of growth.
Of about the same size as S. Wrightianus, but the last whorl is proportionally higher.
Straparolus aratus, nov. sp. (Pl. XXVI. fig. 21.)
Shell small, discoidal, plano-concave above, deeply but narrowly umbilicated below ; whorls five, regularly rounded, slightly embracing, ornamented with numerous thick flexuous ribs, attenuated at the suture and on the margin of the umbilicus.
But for the asymmetrical form, the shell of this species might be mistaken for that of some varieties of Ammonites Jamesoni, notably A. polymorphus interruptus, Quenstedt.
Though the above species of Straparolus are closely allied by their external figures, yet the numerous specimens I have examined exhibit no gradation in their ornamentation from one species to the other, and consequently they should rank as distinct species.
Littorina biornata, nov. sp. (Pl. XXVI. fig. 17.)
Shell ovate, imperforate; spire elongated, acuminate ; whorls eight, subinflated ; anterior whorls with two strong acute encircling ribs, last three whorls ornamented with about eight decurrent thick costae ; aperture subovate, entire ; columella straight, slightly effuse at the base ; base subglobose, smooth.
Dimensions. Length 0.22 inch ; diameter of last whorl 0.08 inch.
Locality. With Straparolus Wrightianus &c. near Lyme Regis, zone of Ammonites Jamesoni (very common).
Turbo cryptaenioides, nov. sp.
Shell turbinated, depressed, much broader than high; spire acute ;
