LINNEAN GENERA OF SHELLS. 



53 



The Teredo Navalis, or ship. worm, insinuates itself into the bottoms of 

 ships, even althoug^h the oak is perfectly sound, and in a very short time 

 rompletely destroys it. This destructive creature was originally brought 

 by our vessels from tropical climates; but has now become an inhabitant of 

 most of the harbours of this island, and is very common in Plymouth Dock. 



It was first proved by that learned and very indefatigable naturalist. 

 Colonel Ge(»rge Montagu, in his supplement to Testacea Britaunica, that 

 tlie aoiinal inhabiting the Teredo, was not a Terebella, but an Ascidea. 



Genus 36 SABELLA. 



Animal a Nereis, with a ringent mouth, and two thicker 

 teiitacula behind the head; shell tubular, composed of particles 

 of sand, broken shells, and vegetable substances, united to a 

 membrane by a glutinous cement. 



Sabella tabifonnis.—FlHte IX. fig. 36. 

 These shells, (if they can be called so) inhabit the sea and fresh water 

 ditches. The Linneaa Sabellse are not testaceous shells, but merely cover, 

 ings made up of extraneous substances ; and may therefore fairly be ex- 

 punged from the collection of the Conchologist. They are included in 

 Lamarck's class Annelides, from the formation of the animal. 



TABLE 



OF THE 



LINNEAN GENERA OF SHELLS, 



WITH LAMARCK'S DIVISIONS OF THESE GENERA: 



I. Chiton, 



II. I-KPAS, 



Hi. Pholas, 



- Panoppea. 



Giycimeris. 



My a. 



Anatirja. 



Lutraria, 

 part. 

 ^ Amphulijsma, 

 I part. 



Corbula 



Uni... 



Hyria. 

 L Vulsella. 



J Solen. 



I Auatina, pa;^ 



