. DR. E. P. WRIGHT ON A NEW GENUS OF TEREDININÆ. 458 
NAUSITORA DUNLOPEI, nov. spec. 
On examining the external portion of either of the valves, we find it to be divided into 
two well-marked portions: the first of these, which would correspond to the * trian- 
gular area or anterior commencement of Forbes and Hanley in 757600, is here quadri- 
lateral; and the second, the body or “ central unguiform portion ” of the same authors, is 
rudely pentagonal. I believe that one of the characteristic marks of Nausitora will be 
found to be the absence of the third portion present in all the species which I have 
examined of Teredo or Xylotrya—i. e. the auricle. 
The “quadrilateral” area is deeply ribbed, and these ribs are notched at minute 
intervals, giving to them a moniliform appearance: the lower side is somewhat oblique, 
and displays a slight convexity; the upper edge is irregular; the free edge is somewhat 
in the form of a semicircle, for the attachment of a false ligament; the fourth side is 
attached to the body, but distinctly marked out from it by a sharply defined suture. The 
body forms a rude pentagon, the base of which is continuous with the upper edge of the 
quadrilateral portion : one side joins on to the same area; the corresponding edge on the 
other side is free; and the two remaining sides are prolonged to form the unguiform por- 
tion or beak. The body is ribbed very much in the same manner as the quadrilateral area, 
and these ribs run at right angles to those on this latter part; they cover two-thirds of 
the surface of the body; on the other third they are lost, first becoming slightly curved. 
The texture is firm and solid, and the greater part of the surface is covered with an 
olivaceous epidermis. 
Internally, the ventral callosity is well marked, being of a broad triangular form. The 
callosity of the hinge-margin is largely developed, and has a small spur-like process 
attached to it. The subumbonal blade is directed inwards and then slightly outwards ; 
its outer edge is smooth, its inner irregular; it is broad and glistening. A little below 
its insertion there is a broad, coarsely striated, glistening lamina of shell, which extends 
across from the inner surface of the quadrilateral portion to within a short distance of 
the beak, 
The dimensions of the larger specimens are—length, from extremity of beak to base of 
body, measured along the valve, 1 inch; breadth, in broadest part, $ inch. 
The pallets are 4 inch long, of which the stalk measures عقب‎ inch. The body is broad, 
slightly concave on its inner surface, which in one specimen is worn somewhat flat ; the 
outer surface is convex and roughly imbricated. A peculiar core-like body is seen running 
through the expanded portion underneath the thick scale-like striz. The stalk is cylin- 
drical, curved, and tapers to a fine sharp point; there is a slight muscular scar around 
the junction of the body with the stalk. 
One pair of valves of the smaller specimen (which wanted its pallets), and one pallet 
from the larger specimen, I have presented to Dr. J. E. Gray for the collection of the 
British Museum; the remaining pallet, still attached, and the larger pair of valves 
have been presented to the Zoological Museum of the University of Dublin. 
Some short time since, I had opportunities of examining the majority of the recorded 
Species of Teredines, of which Dr. J. E. Gray and Mr. J. G. Jeffreys have published very 
VOL. XXIV. 8N 
