TEREDIDiE. 



l^g^ 



species, T. chlorofica, the pallets of which are elongated, with the 

 basal portion, thin, flexuous, the upper lyre-shaped, the extreme 

 two-thirds of their length being covered with a dark crust which 

 has a projecting horn at each angle. The form of these pallets 

 very closely resembles that of Nausitoria, when the tip is broken 

 away ; it may belong to the same genus. 



? TEREDOLiTES, Dcsh. For a cretaceous species, T. clavatus, 

 only known by some tubes which are short, clavate, and in posi- 

 tion, as they occur in the rock or wood, almost parallel to each 

 other. 



[POLORTHUS, Gabb. See page 53, vol. ii.] 



Xylotrya, Leach, Gray, 1847. 



Syn. — Bankia, Gray, 



Distr. — 10 or 12 sp. Universal. X. palmulata, Lam. (cv, 74). 

 E. Indies. 



Siphonal pallets elongated and penniform, the blade con- 

 sisting of articulated pieces radiating obliquely from the style. 

 A species occurs in the fossil wood of the Greensand of Black- 

 down, England. 



TJpEROTis, Guettard, 



Syn. — Guettera, Gray. 



Distr. — U. claua, Gmel. (civ, 49). Tranquebar. 



Tube club-shaped, straight or contorted, growing together in 

 masses ; pallets oval, jagged; valves narrow and elongated. 



KuPHUS, Guettard. 



Syn. — Furcella and Septaria, Lam. Clauseria, Menke. 



Distr. — K. arenarius^ Linn, (civ, 50-52). Philippines. 



Tube penetrating sand, somewhat irregular, very large ; 

 pierced around the base with small scattered perforations, and 

 inclosed by two overlapping convex septa arising from the sides 

 and completely closing the end. These septa appear to replace 

 the valves. 



The tube of the giant Teredo is often two j^ards long and two 

 inches in its greatest diameter ; when broken across it presents 

 a radiating prismatic structure. The siphonal end is divided 

 lengthwise, and sometimes prolonged into two diverging tubes. 



Teredina, Lam., 1818. 



Distr. — T. personata, Lam. (civ, 53,54). Eocene; Europe. 



Yalves with an accessory plate in front of the umbones ; free 

 when young, in the adult connected with the tube. The tube 

 is sometimes concamerated ; its siphonal end is often truncated ; 

 and the opening contracted by a lining which makes it hour-glass 

 shaped, or six-lobed. 



The possession of an accessory dorsal valve connects this genus 

 with the next family ; no siphonal pallets have been discovered. 



