S P I 



[413] 



S P I 



sapphire, with which it had pre- 

 viously been confounded. It is 

 principally met with in Ceylon, 

 Siam, Pegu, and other eastern 

 countries ; it also occurs in drusy 

 cavities, together with Ceylanite, 

 Vesuvian, &c. 



SPINE'LLANE. A variety of dodeca- 

 hedral zeolite. A mineral of a 

 plum-blue or blackish- brown co- 

 lour, found on the banks of the 

 river Laach, near Andernach. It 

 occurs in hexahedral prisms, ter- 

 minated by three-sided summits, 

 whose faces stand on alternate, but 

 different, lateral edges at each ex- 

 tremity. 



SPI'NY. } Having spines, thorns, or 



SPI'NOTJS. j points. 



1. In botany, applied to plants 

 possessing thorns or spines ; also to 

 leaves, the margins of which are 

 beset with thorns. 



2. In anatomy, applied to certain 

 processes of bones. 



SPIRE, (spira, Lat.) That part of a 

 body which shoots up to a point. 

 In conchology, the spire of uni- 

 valve shells consists of all the 

 whorls except the lower one, which 

 is termed the body. The spire is 

 a prominent feature in univalve 

 shells, and upon its being elevated, 

 depressed, &c., depends much of 

 the generic and specific definition. 

 There are several kinds of spire; 

 the depressed spire, when the spire 

 is very flat; the involuted spire, 

 when the whorls are concealed in 

 the inside of the first whorl, as in 

 the nautilus; the reversed spire, 

 when the whorls turn in the con- 

 trary direction to a right-handed 

 screw, &c. 



SP^IFEK. ) (from spira, a spire, and 

 SPIIU'FERA. ) fero, to bear, Lat.) A 

 genus of bivalve shells, distin- 

 guished from terebratula by its 

 very extraordinary internal spiral 

 processes or cones, of which there 

 were two, and from which it ob- 

 tains its name. The genus spirifer 



appears to be met with, in the 

 descending series, first in the lias. 

 It is in the carboniferous limestone 

 that Spiriferae most abound, not 

 fewer than twenty species having 

 been determined as occuring in 

 that deposit. Deshayes recom- 

 mends the entire suppression of the 

 genus Spirifer, stating that all the 

 species may be referred either to 

 Producta or Terebratula. Spiriferse, 

 which are met with in great abun- 

 dance in the grauwacke and car- 

 boniferous series, appear to have 

 become extinct during, or immedi- 

 ately after, the deposition of the 

 lias, above which not any have been 

 discovered. 



SPIEOLI'NA. A genus of microscopic 

 foraminiferous multilocular uni- 

 valves, described by Lamarck, who 

 discovered several species of them 

 in the fossils of Grignon. 



SPIRO'RBIS. A genus of shells belong- 

 ing to the family of the Serpulacea. 

 A familiar example of spirorbis is 

 afforded in the common, small, 

 white, coiled shell so frequently 

 seen upon the shell of the lobster. 

 The spirorbis is found on sea- weed, 

 shells, &c. 



SPI'RULA. (from spira, Lat.) Both 

 a recent and a fossil shell. A genus 

 of multilocular shells, partly spiral 

 and partly straight, the whorls 

 being arranged in a discoidal form, 

 and separate from each other ; the 

 last turn being elongated, and con- 

 tinued in a straight line. The si- 

 phunculus, instead of being mem- 

 branous, is formed by one con- 

 tinuous shelly tube. It appears 

 that the spirula, notwithstanding 

 it possessed a siphuncle, was, alto- 

 gether or in part, an internal shell. 

 The living spirula is an inhabitant 

 of tropical seas; it floats on the 

 surface of the ocean. 



SPI'RULITE. A fossil spirula. Spiru- 

 lites are sometimes termed lituites, 

 from their supposed resemblance to 

 a bishop's pastoral staff. 



