CONCHIFERA. 755 



species. The points of the shell are covered with calcareous inequalities, 

 which are connected by transverse projecting parallel lines at the inside 

 with the margin of the hinge. 



Sp. Pholas Dactylus L., POLI Test. utr. Sic. i. Testae. muUiv. pp. 40 50, 

 Tab. vn. figs, i 1 1, Tab. vnr. ; in the Mediter. and N. Seas, edible, and, 

 as is said, of agreeable taste. PLINIUS speaks of the phosphorescence of 

 this animal in the dark, Hist. not. Lib. IX. cap. 61 ; Pholas crispata L., 

 CHEMN. Conchyl. Tab. 102, figs. 872 874, Pholas costata LAM. (Phol. 

 costatus L.), BLAINV. Malac. PI. 79, fig. 6, &c. Some fossil species are 

 known from the tertiary formations. 



Teredina LAM. Two valves furnished internally with cochleari- 

 form tooth, covered at the hinge with a shield, grown to a calca- 

 reous tube, elongate, conical, closed at one extremity, open at the 

 opposite. (Fossil species.) 



Sp. Teredina personata LAM., Ann. du Mus. xn. PI. 43, figs. 6, 7, BLAINV. 

 Malac. PI. 8 1, fig. 5. 



Teredo L. Mantle tubular, terminated by two tracheae con- 

 crete at the base, open anteriorly for the passage of foot, short, trun- 

 cated. Shell equivalve, gaping on both ends, small, covering the 

 anterior part of the animal like a ring. Animal inhabiting a cylin- 

 drical tube covered with calcareous substance, and adhering to it 

 |by two calcareous pinnae (palmulce) placed at the base of tracheae. 



Pile-worm. These animals live in wood, which they perforate in all 

 directions. The cavity in which they reside is covered with a calcareous 

 incrustation, but the true shell is bivalve and much smaller than the 

 mantle. How they penetrate and bore through the wood is not yet 

 sufficiently explained. They grow in the wood, and do not first enter 

 it as adult animals, for the external aperture, towards which the two 

 tubes (trackece) are turned, is too narrow to allow the inclosed animal 

 to enter, however it may have been able to make itself a way at an earlier 

 period. 



LINNAEUS placed this genus incorrectly between Serpula and Sdbella 

 (amongst the ringed worms), and named the bivalve shell the jaws of the 

 animal. He united all the individuals that had been described up to 

 his time under one species, Teredo navalis, which is a collective name. 

 The species even now are far from being sufficiently distinguished. See 

 SPENGLER Skrivter of Naturh. Selskdbet, 11. i. Kjobenhavn, 1792, pp. 99 

 1 06, and QUATREFAGES Mem. sur le genre Taret, Ann. des Sc. nat. 

 3ieme Se'rie, Tom. XI. 1849, Zoologie, pp. 19 73, PI. I. II. The ana- 

 tomical investigations of the writer named last, are the latest and the most 

 complete : of the internal structure, to say nothing of older writers, notices 

 in modern times have also been given by DESHAYES, in the Exploration 

 scientifique de VAlgerie (1846), and FREY und LEUCKART (Beitrdge zur 



482 



