SPIEOLIKA. 281 



SPHINCTEEULUS. Montf. Lenticulina, B1. A genus of 

 microscopic Foraminifera. 



SPINES. {Spina, a thorn.) Thin, pointed spikes. 



SPINOSE. (Spinosns.) Having spines or elevated points, as 

 Neritina spinosa. Eig. 325. 



SPIRAL. {Spira, a spire.) Eevolving outwards from a central 

 apex or nucleus, like the spring of a watch. A shell or an 

 operculum, may be spiral, mthout being produced into a pyra- 

 mid. Bands of colour, striae, grooves, &c. commencing from 

 the nucleus and following the volutions of the shell, are de- 

 scribed by the above word. 



SPIRALIS. Eydous and Souleyet, A genus of Pteropoda, dis- 

 tinguished by the obliquely spiral form of the shells. PI. xxviii. 

 fig. 581. 



SPIRAMILLA. Bl. A genus of Serpulacea, differing from 

 other Serpulae principally in the characters of the animal. 



SPIRATELLA. Bl. Limacinea, Lam. PL xii. fig. 224. 



SPIRE. {Spira.) The cone or pyramid produced in a non- 

 symmetrical univalve by its oblique revolution downwards from 

 the apex or nucleus. The spire, in descriptions, includes all 

 the volutions above the aperture. See Introduction. 



SPIRIEER. Sow. (Spira, a spire ; fero, to bear.) Order, Bra- 

 chiopoda, Lam. — Descr. Transverse, equilateral; hinge linear, 

 straight, widely extended on both sides of the umbones, which 

 are separated by a flat area in the upper and larger valve ; this 

 area is divided in the centre by a triangular pit for the passage 

 of the byssus ; interior with two spirally convolute appendages. 

 — Obs. This genus, which is only known in a fossil state, is 

 distinguished from Terebratula externally, by the flat area in 

 one valve, internally, by the singular spiral process from which 

 the above name is derived. Most of the species belong to the 

 mountain or carboniferous limestone. PL xii. fig. 214, 215. 



SPIROGLYPHUS. Baudin, 1800. A genus consisting of a 

 Serpula Aucf. which makes a groove for itself in the surface of 

 shells. Serpula spirorbis, var. Dillwyn. PL i. fig. 8. 



SPIROLINA. Lam. A genus of mici'oscopic Eoraminifera. 



