Ten-do.] PELECYPODA. 1019 



pt. 3. 498), that the work of boring is done with the foot. Dr. Dall, 

 however, does not mention Teredo, and he also does not include that 

 genus when he explains the boring of the Pholads, on page 496. 



I am unable to share Mr. Hedley's opinion, for the following 

 reasons : (1) The foot of the shipworms is quite rudimentary, and not 

 of an enormous size as in the Pholads ; (2) I am fully convinced that 

 it is next to impossible to bore successfully in fibrous timber with the 

 soft foot alone, but it is easily understood to be practicable in the 

 softer kinds of rocks ; (3) if the boring were done with the soft foot 

 there would be no noise one could not hear the- shipworms " grinding." 

 .is quoted by Hedley. No doubt the best explanation is given by 

 Brehm in " Illustristes Tieiieben " (Volksausgabe, iii, 842) : According 

 to direct observations the Teredo, when boring, uses the two valves 

 like two jaws or the two edges of pincers, but with the difference that 

 their movements are successive and in planes at right angles to one 

 another. The valves possess (in most of the species) at the anterior 

 margins numerous minute teeth arranged in such a way that the wood 

 is cut up into minute square pieces at each stroke of the valve. The 

 teeth, it is said, are very little worn off, because they do not scrape, 

 but cut. and because during growth of the valves by additional fresh 

 shelly layers they are surpassed by fresh teeth. 



In the Eocene and Miocene periods New Zealand had a species of 

 Teredo (T. Heaphyi. Zittel), which seems to have died out, since it 

 has not been found in the Pliocene. Unfortunately, two introduced 

 species have taken up its place in more recent times. 



Subgen.- 1. TEREDO, s. str. 



Mantle at the base of siphons, and pallets without a cup -shaped 

 fold ; siphons separated near the posterior end. Type : T. navalis, L. 



1. Teredo Bruguieri, Delle Chiaje, 1828. Plate 55, figs. 7, a-d. 



Teredo Brwjieri, Uelle Chiaje, Memorie, iv. 1828, 28, 32, pi. .34, f. 9-12. 

 T. norvegica, Spengler, Ski', nat. Selsk., ii, 1792, 102, pi. 2, f. 46, B, 

 not binomial ; Forbes and Hanley, Brit. Moll., i, 1853, 60, pi. i, f. 15. 

 T. antarctica, Button, C.M.M., 59 ; M.N.Z.M., 133 : Hedley, P.L.S. 

 N.S.W., 1894, 503, pi. 32. f. 6, 7 ; op. cit.. 1898, 95 ; Proc. Austral. 

 Assoc. Adv. Sci., 1901, 248 ; Index, 88. 



Shell globose, valves trilobate, with a rather large anterior area,, 

 the body of moderate size, not slender and produced, and the auricle 

 seated on the posterior shoulder, not dilated ; a dark-brown band on 

 the posterior part of the body. Beaks not prominent, convex, strongly 

 incurved, situate in front of the middle. Anterior end produced, 

 sharply angled in front, the dorsal margin excavated, the basal margin 

 not very oblique, nearly rectilinear, and forming a right or somewhat 

 larger angle with the anterior margin of the body, which is elongate- 

 triangular, moderately broad, its anterior margin is straight, the 

 posterior very lightly convex, and both of about the same length ; 



