44 



Guide to the Invertehrata. 



GALLERY has been by some placed in the Annelida ; the systematic position 



of the whole of these older forms is still, however, uncertain. 

 Table -case 

 72. 



See 



GALLEEY 



VIII. 



Wall- 

 case 1. 



¥iG. 80. — Vaffinella de- 

 pressa. Bast. Miocene : 

 Bordeaux. 



Fig. 81. — Balmitium 

 reciirvum, Childr. 

 Recent : Atlantic. 



Fig. 82. — Hyalma triden- 

 tata, Gmel. Recent : At- 

 lantic and Mediterranean. 

 Miocene : Turin, Sicily, 

 and Dax. 



GALLERY In Ilyolithes { — Theca) the shell is conical, usually straight, 

 sometimes slightly curved, triangular in section, generally smooth, 



72. or with only fine transverse striae ; often provided with an 



operculum. The species vary in size, being usually an inch or an 

 inch and a half long. They range from the Cambrian through the 

 Ordovician and Silurian to the Devonian, and more rarely occur 

 also in the Carboniferous and Permian rocks. 



Fig. 83. — Conularia quadrisulcata, Sby. Coal-measures: Coalbrookdale. 

 a, side-view ; b, back ; c, mouth or aperture of shell. The lower 

 extremity is broken off. 



In Conularia (Fig. 83) the shell is pyramidal in form, tetragonal 

 in section ; each face has a median furrow and is ornamented 

 with transverse smooth or tuberculated ridges, each ridge being 

 angulated in the centre of the face, the apex being directed 

 towards the aperture. The latter is partially closed by an infolded 

 prolongation of each face. The genus occurs in the Ordovician, 

 Silurian, and Devonian, more rarely in the Carboniferous and the 

 Permian formations ; one species has been recorded from the 

 Trias and another from the Lias. 



