USED IN NATURAL HISTORY. 



133 



substance of lichens; it is sur- 

 rounded by a rim and contains 

 the asci, or tubes filled with spo- 

 rules. 



BCU'TELLATED. ^ fr. lat. scutum, a 



SCUTEL'LIFORM. > shield. Shield- 



SCU'TIFORM. ) shaped. 



SCI-'TELLATED (legs). fr. lat. scu- 

 tum, a shield. Having the tarsi 

 covered with scaly plates. 



SCUTIBRANCHIA'TA. fr. lat. scutum, 

 a shield ; branchia, gills. An or- 

 der of gasteropods. 



SCU'TUM. Lat. A shield. 



SCYL'LIUM. fr. gr. skullo, I tear in 

 pieces. Systematic name of the 

 shark. 



SEAM. The line formed by the 

 union of the valves of bivalve 

 shells. 



SEAMS. Thin layers or strata inter- 

 posed between others. 



SECA'LE. Lat. Rye. 



SECONDARIES. Those quills that 

 rise from the second bones of the 

 wings of birds. 



SE'COSTDART FORMA'TIOX. A series 

 of stratified rocks with certain 

 characters by which they are dis- 

 tinguished from the primary rocks. 

 By the term formation geologists 

 understand a series of rocks of 

 the same age. Those rocks which 

 were first formed are called pri- 

 mary those formed next in suc- 

 cession are secondary and so on. 



SECRE'TE. fr. lat. secernere, to sepa- 

 rate. To select and take from 

 the organic fluids, materials pecu- 

 liarly adapted to the purposes of 

 the organ or agent that secretes. 



SECRETED. Separated by the action 

 of organs. 



SKCRE'TIOX fr. lat. secernere, to se- 

 parate. The process by which 

 organic structure is enabled to 

 separate from the fluids circulat- 

 ing in it, oilier different fluids. 

 Each organ according to its pecu- 

 liar structure, differs from the rest, 

 and hence we have the formation 

 of the different fluids, as bile, sa- 



liva, milk, &c. The fluid? thus 

 separated, are termed secretions. 



SECRE'TORT. Belonging or relating 

 to secretion. 



SECTILE. fr. lat. seco, I cut. Ap- 

 plied to minerals which are half 

 way between brittle and mal- 

 leable. 



SE'CULAR. fr.lat. seculum, a century, 

 or period. Semlar elevations are 

 those which take place gradually 

 and imperceptibly, through a long 

 period of time. Secular tides are 

 those which are dependent upon 

 the secular variation of the moon's 

 mean distance from the earth. 

 Secular refrigeration is the periodi- 

 cal cooling and consolidation of 

 the globe from a supposed origi- 

 nal state of fluidity from heat. 



SECUSTD. In botany, unilateral; ar- 

 ranged on one side only. 



SECUNDINE. In botany, that sac of 

 the ovule which rests immedi- 

 ately on the primine, and often 

 contracts an adhesion with it. 



SEED. The seed of a plant is the 

 ovule in its matured state, (p. 66, 

 Book vii). 



SEED-LOBE. The envelope in which 

 the seed in plants is formed. 



SEDENTARY. Not migratory. 



SE'DIMEWT. fr. lat. sedeo, I sit. That 

 which subsides, or settles to the 

 bottom of any liquid ; dregs. 



SEDIMENTARY. Belonging or relat- 

 ing to sediment. 



SE'GMEXT. A section ; a part cut 

 off. 



SEGREGA'TA. fr. lat. segregatus, se- 



Name of an order of 

 An order 



12 



3H 



pirated. 



plants. 

 SELACHI i. fr. gr. selachos. 



of cartilaginous fishes. 

 SELE'NITE. fr. gr. selene, the rroon ; 



from its silvery appearance. A 



variety of gypsum, or sulphate of 



lime. 



SELLA. Lat. A saddle. 

 SEMI. A prefix, denoting a half. 

 SEMT-AMPLE'XICAUL.~ Half stem-era 



bracing. 



