17 



Genus Salteeblla. (N. gen.) 



G-enerie Characters. — Small, slender, elongate-conicaL tubes, consisting 

 of several hollow cones placed one within another, the last one forming the 

 chamber of habitation of the animal. The cross section of these tubes is 

 circular or subtriangular, and they are either straight or gently curved ; 

 ' the surface is concentrically or longitudinally striated. 



I think these fossils, although no doubt allied to SerpuUtes, sufficiently 

 different therefrom to constitute a distinct genus. Their structure is so 

 compact that they are seldom found compressed, while all species of 

 Serpulites are almost invariably in that condition, shewing that , they con- 

 sist in general of something more hke a membraneous sack than a hard 

 shelled tube. 



This genus is dedicated to J. W. Salter, Esq., Palaeontologist of tjhe 

 Geological Survey of Great Britain. 



Sai,terella rugosa. (N. sp.) 



Fig. 22. 

 Fig. — 22. A piece of Limestone with S. rugosa. 



•Description.— This little species is straight, conical, tapering uniformly 

 to an acute pomt. Length from two to four lines, the greater number of 

 the specimens being under three lines ; diameter at large extremity one 

 line in a specimen four lines in length ; the smaller ones are often a little 

 more obtuse. Aperture circular, .equal to about three-fourths the whole 

 diameter. It is not certain that in any of the specimens observed the 

 surface is preserved ; they all appear to be divested of the o^ter covering, 

 and exhibit four to six imbricating sharp annulations in the length of one 

 line, the edges towards the: larger end. These are doubtless the exposed 

 edges of the several sheaths of which the tube is composed. They are 

 usually straight, but some are slightly curved. 



This species must be closely alHed to Serpulites MaQullocIii (Salter), 

 but upon an average they are smaller than those figured by Salter, in the 

 Jour. Geol. Soc. Yol. XV, PI. 13, fig. 31. 



B 



