OP SOUTnERN INDIA. 11 



with a short foot in front, and posteriorly prolonged into two fleshy siphons, separated 

 at, or towards, their terminations. The length of the siphons, and naturally also of 

 the gills, even varies in different individuals of the same species, living in distinct 

 localities. The hrittle structure of the shell is entirely the same in the various 

 genera, as also its peculiar imhrications and their arrangement on the outer sm'face. 

 The presence or absence of a shelly tube does not seem to be of any great importance, 

 because it entu'ely depends upon the cu'cumstances under which the animal lives, 

 whether it does, or does not, secrete a solid tube at all ; and its thickness varies a great 

 deal in different specimens of the same species. I have myself observed species of 

 TEUEDiNiN^s (NuusUoria and Knphus), in which in some places no shelly tube w^as 

 secreted, although the surrounding wood was in such cases always impregnated with 

 mineral substance. The palettes protecting the terminations of the si|)hons and the 

 so-called accessory valves on the shell itself are the only characters which appear to 

 be of any importance in point of classification, and based upon these we retain here 

 the older separation of the family into teredininm and pbol.idin.e. In the former 

 the shape of the palettes has been suggested as the base of generic distinctioUj and 

 in the latter that of the accessory valves. 



a. Sub-family,— TEREBIN IN yE. 

 (teredininj; and kuphin^, or fuecellin^, auctorum). 



Animal secreting a shelly tube, generally closed in front, open behind, the 

 siphons protected by a pair of shelly or horny styles. Shell sub- globular, widely 

 gaping in front, each valve marked externally by a furrow rimniug from the 

 umbones towards the periphery; accessory valves are wanting, but the umbonal 

 muscles are usually covered by a coriaceous ligament ; - boring generally in wood. 



The animals which are included in this sub-family have been separated 

 by Bronn into two families, Teredinana and Fvrcellana (Klassen and Ordnung. d. 

 Thierreiches, vol. iii, p. 476). The distinction is based upon the supposed fact that 

 the animal of Kuphus fov Favcella) arenarius does not possess shelly valves, but merely 

 secretes a shelly tube, closed in front by two partially overlapping lamellae. Tryon, 

 in his Monograph of the Fholadid^, proposed on the same ground a distinct sub- 

 family under the name of kupkinm ; H. and A. Adams in their " Genera of rec. 

 Moll." ii, p. 332, class K. arenarius, {Teredo gigantea of Linnseus,) in the genus 

 Teredo, simply noting " that the apex of the tube is divided at the end by a longitu- 

 dinal septum, and is produced into two separate tubes." This evidently applies to the 

 posterior or siphonal end. No mention is made of the existence or the want of 

 valves, which should distinguish the species from Teredo proper. Deshayes in his 

 first volimie of the Traite element, de Conch., vol. i, pp. 40-47, describes with some 

 detail Knphus under the Lamarckian name of Septaria. He states that the shelly 

 tube is open in front. 



