106 



body glossy, marked with distant, but regular and fine, strias or impressed lines ; 

 anterior auricle placed nearly at a right angle 'with the insertion of the fang, 

 striae rather numerous and waved ; posterior auricle dilated and somewhat re- 

 flected, apex nearly on a level with the crown or umbo of the valve, inner mar- 

 gin free and well defined ; tubercle slight, and not visible when the valve is in 

 a supine position; fang obtuse; apophysis thin and narrow. Pallets long and 

 narrow, bifid in front to nearly half their length, with two corresponding tubu- 

 lar cavities which terminate in separate points like the prongs of a steel fork : 

 underneath they are abruptly sloped towards the bifurcate points, and closely 

 striated in a longitudinal direction ; stalks near as long as pallets, pointed at 

 one end and at the other merging into the pallets. 



Dimensions. — Length (of valves) 7-20ths; breadth 4-20ths." — Jeffreys. 



T. f u s t i c u 1 u s, Jeffreys. 



T. fusticulus, Jeffreys, Ann. and Mag. Nat. Hist. 3d ser. vi. p. 125. 



Hab. — In Cedrella odorata from Leith. 



Description. — " Tube short and straight, with a slight calcareous lining, which 

 is not easily separated from the wood. It is thickened internally at the opening, 

 and has a few transverse wrinkles in that part. 



Valves round, thin, compressed, body smooth, glossy, white under a brown 

 epidermis ; anterior auricle of moderate size, angle about 50°, striae numerous ; 

 posterior auricle round expanded and appressed to body, internal edge well de- 

 fined ; fang broad, obtuse : tubercle small and sunk ; apophysis thin and narrow. 

 Pallets club-shaped, formed of several transverse layers, and externally tuber- 

 culate; stalk twice the leDgth of pallet. 



Dimensions. — Length (of valve) 4-20ths ; breadth nearly as much." — Jef- 

 freys. 



T. spa th a, Jeffreys. 



T. spat ha, Jeffreys. Ann. and. Mag. Nat. Hist. 3d ser. vi. p. 124. 



Hab. — With T. bipartita, in Cedrela odorata, at Guernsey. 



Description. — " Tube rather long and flexuous, detachable, regularly jointed, 

 increasing rapidly from the extremity, inside which there are a few transverse 

 wrinkles and a sharp, but short, siphonal ridge. 



Valves, triangular, compressed, rather solid ; body smooth ; anterior auricle 

 large, angle about 50°, striae exceedingly numerous and fine ; middle area un- 

 usually large and rounded and appressed, internal margin indistinct; fang nar- 

 row and pointed ; tubercle small and sunk ; apophysis narrow. Pallets spade- 

 shaped, in the young state calyciform ; stalk of the same length as pallet. 



Dimensions. — Length (of valves) 6-20ths; breadth nearly as much. A pair 

 of pallets is in the British Museum, from Miss Saull ; and another pair is in the 

 collections of Natural History at the Jardin des Plants. The localities of both 

 the last-mentioned specimens are unknown." — Jeffreys. 



T. subericola, Macgillivray. 



T. subericola, Macgillivray, Mss. Jeffreys, Ann. and Mag. Nat. Hist. 3d ser. 

 vi. p. 122. 



Hab. — Great Britain. 



Description. — Tube rather thin, and adherent to wood, short, of the form of 

 an elongated cone curved at the opening, with internal irregular transverse sep- 

 ta, which are close-set at the extremity. 



Valves oval, rather convex, thin ; body smooth and somewhat glossy ; ante- 

 rior auricle short, angle obtuse, striae rather numerous; posterior auricle nar- 

 row, falciform, reflected at the outer edge, with its apex raised above the crown ; 

 tubercle strong and prominent; fang long, narrow, and incurved ; apophysis 

 rather broad. Pallets short, pear-shaped, compressed, and expanded towards 

 the anterior margin, with a semilunar depression in the middle and a longitu- 

 dinal groove in front ; stalk short and pointed. 



