46 | PALEONTOLOGY OF NEW JERSEY. 
Genus PERISSOLAX Gabb. 
Synopsis of the Mollusca of the Cretaceous formations, by W. M. Gabb, 1861, p. 66. 
The genus Perissolax was founded upon a group of shells, found in the 
Cretaceous formations, which are characterized by a low spire, rather large, 
globose or pyriform body volution, and a rather long anterior beak and 
canal, which is straight or but very little curved, and a columella without 
plaits or folds. Mr. Gabb cites as types P. (Fusus) longirostris D’Orb., 
from Chili, South America, and P. (Fusus) trivolvus Gabb, from the New 
Jersey Middle Marl Beds. From Mr. Gabb’s remarks and the classification 
of his species in his various papers where it is mentioned, he appears to 
have considered it as strongly related to Fusus, although in his original 
description’ of the genus he says: ‘They have nearly the form of the genus 
Tudicla or Haustellum,” the latter of which is usually classed with or consid- 
ered asasynonym of Murex. My. Tryon, in his Structural and Systematic 
Conchology, classes Perissolax under the Buccinide, while Dr. Stoliezka,? 
although quite doubtful of its relations, would appear to indicate it as belong- 
ing to the Muricide near or among the Fulgurine. After studying the 
species herein described, in connection with others from other parts of the 
country, I am inclined to consider them as having their nearest affinities with 
Haustellum in the Muricide, and have so. arranged them. The Fusus longi- 
rostris, D’Orb., I only know from figures, but the Fusus trivolvis Gabb, the 
American type, is figured and described ‘in this volume, the type specimen 
having been used for this purpose. It will be readily seen on comparison 
that it has more resemblance to Haustellum than to the typical forms of 
the genus Fusus, and differs principally in the higher spire and want of 
periodic varices. Some of the species have, however, nodes or short spines 
at stated distances on the periphery. The full characters of the beak and 
canal have not been seen in any of the New Jersey specimens, all the species 
having been described from casts on which these parts are wanting to a 
greater or less extent. There can be but little doubt as to its relations, 
however, with that group of the Mwricide, and none I think as to its valid- 
ity, even should it prove to be identical with Conrad’s genus Pyropsis, to 
which it is very closely related, as it has precedence in point of time. 
—— 
‘Synopsis of the Mollusca of the Cretaceous formations, 1361, p. 66. 
2 Ind. Geol. Surv., Pal. Indica, Cret. Fauna South Ind., vol. 2, p. 113. 
