506 MANUAL OF THE MOLLUSCA. 
M. terediniformis was found in cakes of floating wax on the 
coast of Cuba. (G. B. Sby.) UW. australis in (fossil ?) resin, on 
the coast of Australia. UV. rivicola in timber twelve miles from 
the sea, in Borneo. J. scutata, EKocene, Paris, lines its burrow 
with shell. 
Jouannetia (semicaudata), Desm. (Pholadopsis, Conrad ; 
Triomphala, Sby.) Shell very short, sub-globose; right valve 
longest behind ; anterior opening closed by a callous plate deye- 
loped from the left valve overlapping the margin of the right 
valve, and fixed to the single unsymmetrical umbonal plate. 
Distribution, 4 species. Philippines, Western America. Fossil, 
Miocene —. France. 
Parapholas, Conrad, P. bisulcata, Pl. X-XIIT., Fig. 22. Valves 
with 2 radiating furrows. Distribution, 4 species. Panama, 
Torres Straits. 
XYLOPHAGA, Turton. 
Hiymology, xulon, wood, phago, to eat. 
Types, X. dorsalis, Pl. XXIII., Fig. 23; X. globosa, Sby. 
Valparaiso. 
Shell globular, with a transverse furrow; gaping in front, 
closed behind; pedal processes short and curved; anterior 
margins reflected, covered by 2 small accessory valves ; burrow 
oval, lined with shell. 
Animal included within the valves, except the slender con- 
tractile siphons, which are furnished with pectinated ridges, and 
divided at the end; foot thick, very extensile. 
Distribution, 2 species. Norway, Britam, South America. 
Bores an inch deep, and across the grain, in floating wood, and 
timbers which are always covered by the sea. 
TEREDO (Pliny), Adanson. 
Type, T. Norvegica, Pl. XXIII., Figs. 26, 27. 
Synonyms, Septaria, Lamarck. Hyperotis, Guettard. 
Shell, globular, open in front and behind, lodged at the inner 
extremity of a burrow partly or entirely lined with shell; valves 
3 lobed, concentrically striated, and with one transverse furrow ; 
hinge-margins reflected in front marked by the anterior muscu- 
lar impressions; umbonal cavity with a long curved muscular 
process. 
Animal worm-like; mantle-lobes united, thickened in front, 
with a minute pedal opening; foot sucker-like, with a foliaceous 
border; viscera included in the valves, heart not pierced by the 
intestine; mouth with palpi; gills long, cord-like, extending 
