Xylophaga. MOLLUSCA. TEREDINIDJ5. 
455 
Shell about three quarters of an inch in diameter, with the valves trian- 
gular, and forming a circular hemisphere when closed together, elegantly 
striate in various directions, each with a triangular projection in front bend- 
ing a little inwards; syphons nearly divided to their origin at the junction 
of the accessorial appendages ; the largest or branchial one has the inside of 
the orifice fringed with about twenty small tentacula ; foot with a convex 
extremity ; mouth round ; gullet short, leaning to the left side of the neck ; 
on the right side of the neck are two large glands ; stomach of two distinct 
bags communicating at the loAver extremity ; the intestine begins close to 
the termination of the gullet, is small, dilates into a cavity, containing a hard, 
Avhite globular body of the size of a large pin’s liead. In the intestine Sir 
E, Home found a yellow-coloured pulp, which Mr Hatchett, after examina- 
tion, considered as vegetable saw dust.” 
551. T. nana. — “ Valves rounded and without auricles be- 
hind, a strong conic tooth on the margin above the teeth.” 
Turt Biv. Brit. 16. t. 2. f. 6, 7- — Drifted Avood in Torbay. 
Diameter about an eighth of an inch ; the conical tooth on the margin of 
the hinge pointing rather obliquely. 
Gen. CXXXII. XYLOPHAGA.— Shell globular, oblique, 
equi valve, very open anteally, and closed retrally, furnished 
with accessorial valves about the hinge, which is destitute 
of long curved teeth under the margin. 
552. X. dorsalis. — Shell rounded, with a triangular striated 
projection in front of the head of each, and a longitudinal rib 
on the inside. 
Turt. Biv. Brit. 16. and 253, t. ii. f. 4, 5 — Drifted wood, Torbay. 
Less than Teredo navalis ; a mesial groove on the outside, corresponding 
with the jointed rib on the inside. There is no evidence of its possessing the 
lengthened calcareous syphons or tube, with their basal appendages, of the 
Teredo. It is probably nearly related to Gastrochcena. 
Gen. FISTULANA.-— Shell equivalve, gaping, with a dorsal 
plate over the hinge ; tube closed at the inner end. 
1. F. personata. — Valves transversely striated on the retral half; the fine 
striae on the anteal half regularly and minutely toothed ; dorsal plate thick, 
four-lobed, with rounded edges — Park* Org. Rem. iii. 202, t. xiv. f. 10. — 
Teredo antenautse. Sower, Min. Conch, t. cii» — Imbedded in the fossil wood 
of the London Clay. 
Gen. CLAVAGELLA. — Tube open at the outer end, termi- 
nating at the inner claviform extremity in tubular pro- 
cesses ; one of the valves cemented to the tube. 
1. C. coronata. — Tube elongated, crowned with dichotomously branched 
tubes around a sulcated disk Sower. Min. Conch, t. cccclxxx.— -Lowcto/j 
Clay. 
