MONOGRAPH OF AMERICAN SHIPWORMS. 31 



change of curve at the junction of the anterior median with the 

 posterior median portion. The posterior median portion is marked 

 by coarse transverse wrinkles on its anterior third, from which lesser 

 lines of growth take a sudden upward curve and extend partly over 

 the rest of the shell. The posterior median portion is suddenly de- 

 flected inward, giving this portion of the shell a truncated appear- 

 ance at the posterior margin. This part is finely granulose above 

 the median portion of the posterior auricular part, while ventrally 

 it is faintly longitudinally grooved. The posterior portion of the 

 shell is produced into a short auricle, which is marked by the con- 

 tinuation of the feeble grooves extending over it from the posterior 

 portion of the median part. The umbonal knob has a strong, nar- 

 row, blade-like tooth extending obliquely into the cavity. A strong 

 oblique shelf for muscular attachment extends from the umbonal 

 tooth to the ventral termination of the posterior auricle, overarching 

 the umbonal cavity. The blade for muscular attachment is thin, 

 short, and decidedly flattened. It is inserted under the umbonal 

 tooth, extending obliquely backward, the tip pointing to a position 

 midway on the ventral edge of the posterior part. In Teredo in 

 the restricted sense the blade usually has its flat surface parallel to 

 the ventral curvature of the interior of the shell, while here the 

 reverse is almost true, for the narrow edge almost parallels the in- 

 terior. The extreme ventral portion of the median part is provided 

 with a strong rounded knob, while the middle of the median por- 

 tion is decidedly roughened within. The pallet's are paddle-shaped, 

 cupped at the distal extremity, with a long, rounded stalk and short 

 ovate blade. 



The type. Cat. No. 338240, U.S.N.M., was taken by Mr. A. Eeyne, 

 of the Agricultural Experiment Station, at Paramaribo, Dutch 

 Guiana, from greenheart wood {Neotandra rodiaei Schomburgk), 

 which was believed to be immune to shipworm attacks. Cat. No. 

 345347, U.S.N.M., contains specimens from Surinam. 



The type measures : Height, 12.2 mm. ; length, 12.3 mm. ; thick- 

 ness, 13.4 mm. The pallets measure: Length, 7.2 mm.; diameter, 

 2.5 mm. 



TEREDO (NEOTEREDO) MIRAFLORA, new species. 

 MIEAFLORA SHIPWOBM. 



Plates 24, 25. 



Shell large, subglobular, white. The anterior portion with a mod- 

 erate sinus which in adult specimens is plugged up with a heavy 

 callus. From the edge of this callus, which is reflected, the dental 

 ridges bend slightly downward and then forward, spreading out in a 

 fan-shaped manner, separated at the posterior extremity by spaces 



