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Show Xll SYSTEMATIC INDEX. Thethys Scyll::ea Glaucus Laniogerus Eolidia Cavolina }t~labellina Tergipes Busiris Placobranchus INFEUOllRANCHIATA Phyllidia biphyllidia TECTIBllANCHIAT A Pleurobranchus Pleurobranch::ea Aplysia Dolabella Notarchus Bursatella Akera Bull rea Bulla Akera proper Gastropteron Gastroplax HETEROPODA Pterotrachea Carinaria Atlanta Firola Timorienna M:onophora Phylliroe PECTINIBRANCHIAT A TnocHOIDA. Trochus Tectarium Calcar J{otella Cantharis Infundibulum Telescopium Trochus Solarium Evomphalus Turbo Turbo proper Delphinula Pleurotoma Turritella Scalaria Cyclostoma Valvata Paludina Littorina Monodon 341 341 342 342 342 342 343 343 343 343 343 S44 344 344 345 345 346 347 347 347 348 348 348 349 349 350 351 352 352 352 352 353 353 353 354 355 355 356 356 356 356 356 356 357 357 357 357 357 358 358 358 359 359 360 360 361 361 Phasianella 362 Ampullaria 362 Lanista 362 Helicina 363 Ampullina 363 Olygira 363 ~elania 363 Rissoa 363 Melanopsis 363 Pirena 364 Act::eon 364 Pyramidella 364 Janthina 364 Nerita 365 Natica 365 Nerida proper 365 Velnta 365 N eritina 365 Clithon 366 CA.PULOID.A. 366 Capulus 365 Hipponyx 366 Crepidula 367 Pileolus 367 Septaria 367 Calyptrcea 368 Siphonaria 368 Sigaretus 368 Coriocella 369 Cryptostoma 369 BucciNOID.A. 369 Conus 3ro Cyprcea 370 Ovula 371 Ovula proper 371 Volva 371 Terebellum 371 "oluta 372 Oliva 372 Volvaria 372 Voluta proper 373 Cymbium 373 Voluta 373 Marginell:l 373 Colombella 373 Mitra 374 Cancellaria 374 Buccinum 374 Buccinum proper 374 Nassa 375 Eburna 375 Ancillari:l. 375 Dolium 375 Doli urn proper 375 Perdix 376 Harpa 376 Purpura 376 Monoceros 376 FIRST GREAT DIVISION OF THE ANIMAL KINGDOMw CLASS III. REPTILIA. The disposition of the heart in Reptiles is such, that at each contraction, a portion only of the blood it has received from the different parts of the body is transmitted to the lungs, the remainder returning to those parts without having passed through the pulmonary organs, and without having respired. The result of this is, that the action of oxygen upon the blood is less than in the Mammalia, and that if the quantity of respiration in the latter, in which all the blood is compelled to pass through the lungs before it returns to the rest of the body, be expressed by a unit, that of Reptiles will be expressed by a fraction of a unit, so much the smaller, as the quantity of blood transmitted to the heart at each contraction is less. As it is from respiration that the blood derives its heat, and the fibre its susceptibility of nervous irritation, the blood of reptiles is cold, and the muscular energy less than that of Quadrupeds, and much less than that of Birds; thus we find their movements usually confined to crawling and swimming ; for, though at certain times several of them jump and run with considerable activity, their habits are generally lazy, their digestion excessively slow, and their sensations obtuse. VoL. II.-A \ |
