OP SOUTHERX INDIA. 17 



4. Teredo (Uperotes ?) glomerans, StoUczka, PL I, Figs. 4-5. 



T. (Uperot.J tiibuUs varie tortis, scepe acQlomeratis, Icevigatis, tenuibus, termina- 

 tionibus anticis clansis, via: inflatls, subtruncatis. ValcuUs testce ignotis. 



This species is based upon two tubes fouucl in a coarse, conglomeratic sandstone. 

 They are variously contorted, and one of them (of which a representation is given 

 in ligui'e 4 on plate I) is extremely like some of the tubes of the recent Uperotes 

 clava, which generally bores in cocoanuts, or in floating pieces of wood. The tubes 

 are rather thin, smooth on the surface, with occasional projecting laminae on the tm-ns 

 or bendings ; they are sub-truncated anteriorly and closed, but not particularly 

 enlarged. No shell has been observed, nor any division or concameration at the 

 posterior end, such as often occm*s in true Teredo or in Kiip)hns. 



Locality. — ComarapoUiam, in a greyish coarse sandstone. 



Formation. — Arrialoor group. 



b. Sul-familij,—PnOLAI)INjE. 



The animals of the pholadinm resemble in general structure those of the 

 TEiiEuiyiN^, but they never grow to the same great length ; consequently the gills are 

 shorter in the former. The greater part of the body is covered with the shell, 

 formed by the two ordinary, or several other accessory, valves ; the mantle is cleft in 

 front to admit of protruding a small foot. The siphons are united nearly up 

 to the end, and do not, as a rule, secrete any palettes. A great peculiarity of most 

 of the PHOLADiNM is the reflection of one part of the anterior adductor muscle 

 towards the beaks, often forming here a more or less cellular secretion, and in some 

 way replacing the ligament. This last is generally absent ; only in a few instances 

 rudiments of it were observed. 



The shell is, as I have already noticed, formed in all the Pholadidm on the same 

 principle. The valves generally are equal, inequilateral, with an internal apophysis 

 under the beaks, without hinge teeth, more or less gaping in front, and on the 

 surface with variously arranged imbrications which are sharpest on the front 

 part of the valves. An important character of a large nimiber of the shells of 

 PMOLADiNM is the presence of the above-mentioned shelly reflection of the antero- 

 superior margin of the valves upon the beaks, covering these partially or totally. 

 A still more important distinction of tliis sub-family from the former is the presence 

 of accessory valves* in almost all pholadinm. The arrangement, form, and f)osi- 

 tion of these valves has been selected as the principal basis for generic distinctions 

 in the same manner as the palettes in the teredininm. They are no dovibt of great 

 importance, for their chief object appears to be to give the two large valves a certain 

 fixed position during the act of boring, when they could easily be dislodged ; but 

 because these supplementary valves are in constant use their form is greatly variable, 



* Leac-h introduced a special nomenclature foi- these valves as regards their position. They may be called itmbonic, 

 pre- or post-umhonic, antero-superior, aiitero-inferior, anterior and posterior, ventral a.ui\. siphoiial ; ih.e sigmfi^aXwa 

 of these terms does not requii'e any further explanation. 



