542 



G. C. Crick — -On Hoplites from the Gault. 



the ventral area is occupied by a well-marked and sharply-defined 

 channel with a row of tubercles on each side, the tubercles on one 

 side usually alternating with those on the opposite side, whereas 

 in the present specimen the median part of the periphery (see 



Deformed example of Soplites tuberculatiis, J. Sowerby, sp., from the Gault, 

 Folkestone. «, left lateral view ; b, front Tiew, showing the single row of 

 tubercles on the periphery and the asymmetry of the last septal surface, 

 si indicating the siphonal lobe ; c, peripheral view, showing the single row of 

 tubercles ou the periphery and the feeble, imperfectly-defined groove on the 

 right (left in the figure) side at the base of the tubercles. Drawn of the 

 natui'al size from a specimen in the British Museum collection. 



Figs, h, c) of the whole of the outer whorl is occupied by a single 

 row of rounded .and nearly equidistant tubercles. A careful 

 examination of the specimen, however, shows that the whorl is 

 not quite symmetrical ; that the row of tubercles is not quite 

 central, but placed a little to the left of the median line ; and that 

 on the right ' at the base of the tubercles (see Figs, h and c) there 

 is a very feeble, imperfectly-defined groove. As we have already 

 remarked, the anterior end of the specimen is formed by the last 

 septum (see Fig. h). This is not quite symmetrical, the siphonal 

 lobe [si] being clearly on the right of the median line, and the 

 lobes and saddles on the right side consequently smaller than those 

 on the left. It is quite clear that the specimen is deformed, and 

 there can be no doubt that it is a deformed example of Soplites 

 tuherculatus. It seems, then, that the tubercles occupying the 

 periphery belong chiefly to the left side, but since the ribs on 

 the right side pass across the very feeble and imperfectly-defined 

 groove, and are also joined to the median row of tubercles, this 

 row may represent also the tubercles belonging to the right side. 

 This opinion is supported by the sliajje of the tubercles, for in the 

 present specimen these are nearly circular and sometimes even 

 transversely elongated in cross-section, whereas in the normal form 

 of the species they are laterally compressed. 



^ The terms ' right ' and ' left ' are here used in a strictly morphological sense. 



