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YEN 



the disturbances, and other processes in 

 which they originated, may have taken 

 place at periods long antecedent to the 

 creation of our species, we may reason- 

 ably infer, that a provision for the comfort 

 and convenience of the last, and most 

 perfect creatures He was about to place 

 upon its surface, was in the providential 

 contemplation of the Creator, in His pri- 

 mary disposal of the physical forces, 

 which have caused some of the earliest 

 and most violent perturbations of the 

 globe." 



VEINED. Variegated ; streaked ; marked j 

 with lines, either parallel to, or intersect- 

 ing, each other. 



VEIN-STONE. The earthy, stony, saline, or 

 combustible substance, which contains the 

 ore, or is mingled with it, without being 

 chemically combined, is called the gangue, 

 or vein-stone. 



VE'NA CA'VA. A large vein which trans- 

 mits the blood from the extremities to 

 the heart. There are two venae cavae ; 

 the superior or descending, which con- 

 veys the returning blood of the head, 

 neck, superior extremities, and part of 

 the thorax ; and the ascending, which 

 returns the blood of the lower extremi- 

 ties, abdominal viscera, &c. These two 

 great veins pour their accumulated tor- 

 rent of blood into the general reservoir, 

 the heart. 



VENERICA'RDIA. A genus of equivalved, 

 inequilateral, marine, oblong bivalves ; 

 ribbed longitudinally on the outside ; two 

 thick hinge-teeth disposed obliquely, and 

 in the same direction : muscular impres- 

 sions two. Venericardiae are found recent 

 and fossil. The recent are met with at 

 depths of the ocean varying to fifty fathoms 

 in mud and sands. Fossil venericardiae are 

 found in the secondary and tertiary for- 

 mations. Dr. Mantell enumerates se- 

 veral species as occurring among the fos- 

 sils of the Sussex strata ; Venericardia 

 planicosta, and V. acuticosta, in the Lon- 

 don clay ; V. Brongniarti in the Bognor 

 sandstone ; and one species in the chalk 

 marl. Mr. Parkinson states that the 

 most beautiful species of this genus is 

 V. planicosta, a remarkably thick shell, 

 obliquely cordated, with flat smooth longi- 

 tudinal ribs : one specimen in his pos- 

 session measured four inches and a half. 



VE'NTRICLE. (from ventriculus, Lat. ven- 

 tricule, Fr.) A chamber or cavity ; the 

 stomach. A term applied to different 

 cavities of the body. The heart contains 

 two chambers distinguished as the right 

 and left venjtricles, as well as two others, 

 termed auricles. Certain cavities found 

 in the brain are also called ventricles. 



VE'NTRLCOSE. ) 1. In botany, applied to 



VE'NTRICOUS. 5 parts of plants which are 



distended, bellied, or swelling out in the 

 middle. 



2. In conchology, applied to shells, in- 

 flated, or swelling in the middle. 



VKNTRI'CULITE. A zoophyte found fossil 

 in flints and in the chalk. Dr. Mantell 

 has fully described different species of 

 ventriculites in his Geology of the South- 

 East of England, and from that work, 

 and from his Wonders of Geology, I 

 have made the following extracts. The 

 ventriculite, when living, must have been 

 of a cyathiform figure, and composed of a 

 tough, jelly-like substance, capable of 

 expansion and contraction. The smaller 

 extremity was attached to the rock by 

 root-like processes ; the outer tissue con- 

 sisted of a net work of cylindrical, perhaps 

 tubular, fibres ; the inner surface of the 

 funnel-like cavity was studded with poly- 

 piferous cells or openings. The speci- 

 mens enveloped in flint are usually of a 

 cyathiform or turbinated shape, while 

 those imbedded in chalk are more fre- 

 quently expanded into a broad circular 

 disk. When contracted into a cylindrical 

 form, the ventriculite is from one to six 

 inches in length ; when expanded, its 

 diameter generally exceeds nine inches : 

 the thickness of its substance is rarely 

 more than 0*2 inch. 



Whether the recent ventriculites were 

 stationary, being confined to one spot by 

 their radical processes, or possessed a 

 power of locomotion, cannot be posi- 

 tively ascertained ; but Dr. Mantell con- 

 siders it more probable that, like the alcyo- 

 nia and actiniae, they were permanently 

 attached to the rock on which they grew. 



VE'NUS. (from Venus, the goddess of 

 beauty.) A genus of exceedingly beauti- 

 ful marine bivalves. Equivalve, inequi- 

 lateral, subglobose, transverse shells, the 

 frontal margin flattened, with incumbent 

 lips ; hinge with three teeth, all of them 

 approximate, the lateral ones divergent 

 at the tip. The middle tooth, which is 

 sometimes bifid, is placed straight, and 

 the one on each side obliquely. The 

 shells of this genus have only been known 

 to inhabit the ocean ; they are found at 

 depths varying to fifty fathoms, lurking 

 in mud and coarse sands. Some of the 

 shells are of the most elegant and beauti- 

 fully diversified description, being rugose, 

 striated, and ribbed. Twenty-five spe- 

 cies have been discovered in the seas of 

 our coasts. Lamarck enumerates six fos- 

 sil species which are found in the neigh- 

 bourhood of Paris, and Dr. Mantell, five 

 species as occurring in the Sussex beds, 

 namely, Venus Ringmeriensis in the chalk 

 marl, and four species, V. parva, V. an- 

 gulata, V. Faba, and V. ovalis, in the 

 Shanklin sand. 



