LAMELLIBEANGHIATA OF THE LOWEE MAELS. 191 



TEREDID^. 



Genus TEEEDO Linn 



Teredo irregularis. 

 Plate XXV, Figs. 18 and 19. 



Teredo irregularis Gabb. J. A. N. Sci. Phil., new ser., Yol. lY, p. 393, PL LXYIII, Fig. 



19. Synopsis, p. 174. Meek, Check-list, p. 16; Geol. Surv. N. J., 1868, 



p. 727. 

 Comp. T, {Uperotisf) contorta Gabb. Proc. A. N. Sciences, 1861, p. 323. 

 Polorthus irregularis Gabb. P. A. N. Sci., 1861, p. 366. 



Tube, as known by the casts, of rather large size, often exceeding half 

 an inch in diameter and of an undetermined length, extremely contorted and 

 irregular in its direction, and frequently strongly annulated. Shell of pro- 

 portionally large size, extremely ventricose, and inflated along the dividing 

 ridge, the band on which is proportionally broad. Valves very short and 

 truncated at each end, the basal part being rather sharply pointed. Pallets 

 unknown. 



The only examples representing the shells of this species are two imper- 

 fect casts of single valves found at the bottom of casts of tubes, and both 

 represent the markings of the inside of tlie valve. One of them is that 

 described by Mr. Gabb, and is figured on the plate. The other is too 

 obscure to furnish any characters whatever. The casts of the tubes only 

 are known beyond these, and are all very fragmentary. Some of them 

 show evidences of having been divided by vesiculose partitions at irregular 

 distances, and others are strongly annulated with strong projecting lamella 

 at the annulations on the outside of the tube, as if it had been fringed at 

 regular intervals ; the fringes projecting into the surrounding material, 

 which, judging from the longitudinally fibrous character of several of them 

 may have been of a woody nature, impregnated in some instances to a 

 depth of an eighth of an inch by mineral matter, which has hardened and 

 preserved a coating to that depth. None of the tubes yet observed preserve 

 the outer extremity, to show if it has or has not been divided by a septum. 



