and Limnoria terebrans. 123 



two feet and a half. In reply to certain queries respecting the 

 size, kc. of the Teredo in tiie east, Captain Fayrer favoured me 

 with the following remarks, dated Portjjatrick, 9.d January 1834. 

 " Having been many voyages in command to India, particular- 

 ly to Bengal, I have frequently there had opportunities of see- 

 ing the destructive effects of the Teredo, and so far as my me^ 

 mory serves me, without having actually specimens to refer to, 

 should at once pronounce those at Portpatrick the same species. 



1 do not think that I ever saw larger specimens in India than I 

 have observed here." 



Of the primary valves, the largest from Portpatrick are from 

 the hinge to the pointed margin ^ of an inch in length, diameter 

 the same. The opercula vary much in form in different speci- 

 mens, but are generally similar in length to the primary valves 

 in the same individual, and like them are covered more or less 

 with an epidermis. The greatest diameter of the testaceous 

 tube or case at the larger end, is | of an inch, at the smaller it 

 varies from 1| to 3 lines. All of the specimens have from 1^ to 



2 inches and upwards of the smaller end of the tube greatly con- 

 tracted within by lamina?, also the partition producing the double 

 aperture extending but a few lines from the very extremity. The 

 greatest thickness of the shell is at the smaller end, where, at 

 the commencement of the laminae, its consistence is from ^^ to 

 j^g part of an inch ; from this it becomes gradually thinner to- 

 wards the greater end, which, in the very largest specimens 

 (those some inches above two feet) is found to be closed up, but 

 in several others there is no deposition whatever of testaceous 

 matter for some distance from the termination of the cell. In 

 one perforation about 20 inches long, the body of the animal 

 has had no testaceous covering for the last 3^ inches ; in two 

 other cells of about 2 feet, no deposition appears for 4^ and 4| 

 inches from their termination. 



All the timber at Portpatrick in which the Teredo had form- 

 ed its habitation is pine,* and perhaps to this circumstance the 

 superior size of the animal may chieffy be attributed. On this 



• Captain Fayrer informs me, that at Calcutta he has seen the Teredo in 

 Teak, Smoo, S'aul {both allied to the Teak, but of a harder quality), and other 

 woods used in ship-building, and has known it in the Hoogl y Itiver to destroy 

 the keel of a vessel atloat, in the short space of four or five months. 



