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THE NAUTILUS. 
NOTES ON THE SOFT PARTS OF TROCHUS INFUNDIBULUM WATSON 
With an account of a remarkable Sexual Modification of the 
Epipodium, hitherto undescribed in Mollusca. 
BY WM. H. DALL, CURATOR DEPT. OF MOLLUSKS, U. 8. NAT. MUSEUM. 
The presence of a verge, or intromittent male organ, has hitherto, 
among the Rhiphidoglossate Mollusks, been recorded only in Ner- 
itina (Claparédé) and certain Limpets. The organ as it exists in 
Neritina and Nerita, is so short and obscure that its function and 
even its existence has been called in question. When I showed its 
existence in the rather anomalous Addisonia paradoxa and Cocculina 
spinigera, curious deep-sea limpets, it was questioned whether they 
were not peculiarly modified Tcenioglossa. 
Since then, in several deep-sea Mollusks, such as Rimula, Marga- 
rita and others indisputably belonging to the Rhiphidoglossa, I have 
found a well-developed verge; and there is little doubt that the an- 
cestors of this group, as well as of the Twnioglossa, were so provided, 
and that some of these deep-sea forms have retained the organ now 
generally obsolete in their shallow water congeners. In combination 
with this survival, one of the species, Trochus infundibulum Watson, 
offers a singular and very interesting special modification of the an- 
terior portion of the epipodium on the right side, which appears 
worthy of particular attention. 
The soft parts of this species afford several notes of interest. The 
external parts, except the eyes, are white. The foot is wide, straight 
and double-edged in front, and, as far as one can judge from speci- 
mens contracted in alcohol, must have been somewhat pointed or 
produced at its anterior corners in life. The sides of the foot are 
nearly smooth, below the epipodial line. 
The muzzle issmall and slender at its proximal end, enlarged and 
transversely semi-lunar at its distal extremity. The oral surface of 
the muzzle is smooth, the mouth very small; the oral disk is flat 
and produced on each side into a thin linguiform lappet, with simple 
and entire edge. These lappets are remarkably long, their ends 
reaching as far as the ends of the true tentacles, and serve as tactile 
organs, like the oral tentacles of the Lepetida, or the much smaller 
lappets of Aemea. When not feeding, or seeking food, these lappets 
would seem to be applied to the sides of the foot below the epipodium. 
