A C I [ 



names, the rery remarkable form 

 of the head or shield of this trilo- 

 bite, the posterior end of its central 

 lobe projecting over the body in 

 the form of a stomacher, and render- 

 ing it totally distinct from any pub- 

 lished figure, induces me to propose 

 it as a new genus." Two species 

 have been described, namely A.cidas- 

 pis Brightii and Abispinosus. They 

 occur in the Wenlock limestone of 

 the Malvern Hills. 



ACI'DIFIABLE. Any substance capable 

 of being converted into an acid, by 

 the union of an acidifying princi- 

 ple without decomposition. 



ACL'DULOUS. (acidulus, Lat.) Slightly 

 acid ; sub-acid ; sourish. 



ACINA'CIFORM. (from acinaces and 

 forma, Lat.) Cimiter shaped; a 

 term applied to leaves, one edge of 

 which is straight and thick, the 

 other curved and thin. 



A'CINOSE. Iron ore. A variety of 

 iron ore found in masses, and com- 

 monly lenticular. Colour, gene- 

 rallj T , brownish red : lustre metallic : 

 texture granular : hardness 5 to 9 : 

 brittle. 



A'CINTJS. (Lat.) Acini PL Each 

 separate part of a compound berry 

 containing a seed : compound ber- 

 ries consist of many simple acini 

 united together, as the raspberry, 

 blackberry, &e. 



ACOTYLE'DON. (from a, priv. and KOT- 

 v\^wv f Gr.) A plant whose seeds 

 have no cotyledon, or side-lobes. 



ACOTYLE'DONOTIS. Plants, whose em- 

 bryos have no lobes, or seminal 

 leaves ; not having cotyledons, or 

 seed lobes. 



ACROCERAU'NIAN. (from axpo* and 

 Kepawos, Gr.) A term given to 

 some mountains, supposed to be 

 especially subject to the effects of 

 lightning. 



A'CROGEN. (from dV/>o<? and ^ewdw, 

 Gr.) An acrogen is a cylindrical 

 plant growing at its point only, 

 and never augmenting in thickness 

 after once formed. 



] 



ACT 



ACRO'MIOX. (from anpoa and 



Gr.) The humeral extremity of 

 the spinous process of the scapula ; 

 situated over the upper end of the 

 humerus, and contributing to the 

 protection of the shoulder joint. 



A'CROSPIEE. (from a/c/aos and GTrelpa 



Gr.) The shoot or sprout of a 

 seed, also called the plume or 

 plumule. 



ACTEONELLE. A genus of cylindrical 

 smooth univalves, with elevated 

 spire, aperture entire, lengthened, 

 moderately wide anteriorly, narrow 

 posteriorly ; columella smooth, 

 rounded ; lip thin. It occurs fossil 

 in the oolite. 



ACTI'NIA. The sea-anemony, a genus 

 of the order Vermes mollusca. The 

 fleshy body of the actinia is fre- 

 quently ornamented with bright 

 colours, and exhibits numerous ten- 

 tacula placed round the mouth in 

 several ranges, like the petals of a 

 double flower, from which it has 

 obtained its name of sea-anemony. 



ACTINO'CERAS. A genus of chambered 

 fossil shells belonging to the family 

 of the Orthocerata, and established 

 by Brenn ; it is a straight conical 

 camerated shell with septa, as in 

 Orthoceras, the siphuncle is external 

 but divided into chambers, and 

 within it is a continuous tube which 

 appears to have been capable of 

 contraction and expansion, and is 

 furnished with verticillate radii 

 which connect the tube with the 

 walls of the syphon. Lycett. 



ACTING COMAX. A genus of fossil 

 shells, having the form of belem- 

 nites. 



ACTINOLEPIS. An ichthyolite of the 

 old Red Sandstone. 



ACTINOCRINITES. (from 0/CT/J/OJT09, 



radiated, and Kplvov, a lily Gr.) 

 Radiated, lily-shaped animals. A 

 genus of fossil encrinites established 

 by Miller. There are many species, 

 some of which are found in the 

 Silurian rocks and in the carboni- 

 ferous limestone. Mr. Phillips says 



