756 CLASS xir. 



Kenntniss wirbelloser Thiere, Braunschw. 1847, 4to, s. 4653). They are, 

 according to QUATREFAGES, of distinct sex, but the male individuals are 

 much rarer than the female. 



For the distinction of species recourse is had amongst other characters to 

 the form of the two small shovel-shaped calcareous plates which are placed 

 below on the mantle, at the base of the tracheae, and are commonly named 

 palmulce. One species, famous for the injury it caused to the piles of the 

 dykes in Holland, in the beginning of the last century especially, might be 

 named Teredo Sellii (Teredo navalis L. et auctor. in part, Teredo batavus 

 SPENGLER). It is figured in the work of SELLIUS and in BLUMENBACH 

 Abh. naturhistorischer Gegenstdnde, No. 89. The palmulce are fixed on a 

 short pedicle, inversely triangular, and terminating at the broad end on 

 each side in a point. Piles that had been driven only six or seven weeks 

 previously were seen to be entirely eaten through by this worm, and robbed 

 of all their strength. In this way the island of Walcheren was in 1730 

 threatened with destruction. From time to time the same mischief was 

 discovered in other places, especially on the Zuiderzee near Medemblik, 

 Lambertshagen, &c. ; West-Friesland was forced in consequence to mask 

 its dykes with large stones, which being brought into the country from 

 abroad, occasioned a great expense; according to MARTINET, Catechismus 

 der Natuur. in. bl. 33, f. 5,600,000 were applied to the first repair of these 

 dykes. Since the middle of the last century the mischief has much diminished, 

 so that hence may be explained the fact, that even in the national museums 

 only a few specimens of Teredo are preserved. This injury to our dykes 

 was the occasion of many writings, which however contributed little to 

 the advancement of science. We suffice ourselves with citing the large 

 work of G. SELLIUS, Histor. nat. Teredinis. Traj. ad Ehen. 4to. Fossil 

 Teredines also are found in the tertiary formations and in the chalk strata. 



Septaria LAM. 



Sp. Septaria arenaria LAM., Serpula polythalamia L., RUMPH. Amb. Rari~ 

 teitk. Tab. 41, figs. D, E. A long conical tube, with irregular constrictions 

 and corresponding septa projecting internally; at the thin end are two 

 calcareous pipes. The description of RUMPHIUS already indicates that the 

 enclosed animal has much agreement with Teredo. This was confirmed by 

 the discovery of a similar species in the Mediterranean a few years ago by 

 MATHERON (Septaria mediterranea DESH. ConcTiyl. PI. i, figs. 9, 10). The 

 animal with its small shell is contained in the tube that sticks in the 

 sand. Perhaps this genus might be united with Teredo, as has been the 

 Indian species figured by HOME under the name of Teredo giganteus (Phil. 

 Transact. 1806). 



Family XXIII. Tubicola. Mantle sacciform, cloven ante- 

 riorly for the passage of a rudiment of foot ; two tracheae conjoined 

 into a fleshy pipe. Animal clavate anteriorly. Bivalve shell 

 gaping, without cochleariform process, with hinge edentulous 

 linear, contained in a calcareous tube, or concrete with the wall of 

 the tube. 



