304 MAZATLAN UNIVALVES 
Maravignia, Aradas & Maggiore, 1842. 
Phasianema, Searles Wood, Crag Moll. 1842. 
Animal with two frontal lobes between the tentacles; shell 
umbilicated, sculptured, mouth semilunate. 
404, FossaRUS TUBEROSUS, 2. 8. 
F. t. “Fossaro angulato” simili, sed anfr. vi., quarum iv. 
tuberost, rubri, concentrice tenuissime lirati, interdum carinati ; 
anfr. uu. normalibus, albido-fuscis, plus minusve tumentibus, 
carinis et liris plus minusve irregulariter extantibus ; labio 
excavato; umbilico et statur&d maxime variantibus ; epider- 
mide interdum setosd. 
=P irichotropis, sp. 1. P. P. C., Cat. Prov. 
Comp. Adeorbis scaber, Phil. in Zeit. f. Mal. 1848, p. 129. 
(Hab.— Panama.) 
The three individuals found vary extremely in form, markings 
and umbilicus. They agree however in the remarkable char- 
acter of the vertex, which is like that of (Tuberia) supralirata, 
and is set rather slanting on the body whirls. These are 
either regular, or suddenly bulging, as in the polymorphous 
Dundry fossil, Cirrus nodosus, Sow., and are marked with 
irregular coste, two or more of nicht develop into keels. In 
the spreading form the umbilicus is very large ; in the compact 
state very small. A young spreading sp. measures 032 by °03, 
div, 90°; a larger compact one, long. °043, long. spir. *015, 
lat. °38, ide 60°. 
Hab.—Mazatlan; extremely rare, off Chama and Spondylus ; 
LT’pool Col. 
Tablet 1700 contains the two extreme specimens. 
405. FossARUSs ANGULATUS, 7. S. 
F. t. subovoided, tenui; albido-fuscd, atro-purpureo irregu- 
lariter maculosd ; spird subacutd, anfr. iv. quorum duo nucleosi, 
leves ; carinis angulatis circiter vi. quarum due tresve extan- 
tiores sunt, striulisque spiralibus creberrimis, ab epidermide 
tenuissime cancellatis, eleganter exculpta ; umbilico magno, acute 
carinato ; labro tenui, angulato ; PEM aH continuo ; labie 
via excavato, haud plicato. 
