. Elementary text-book of zoology. Zoology. 52 MOLLUSCA. keel, with caudal gland and mucous aperture at end of body. A. cmpiricorii m Fer., Umax L. Respiratory aperture behind the middle of the right edge of the mantle. Sexual opening far removed from respira- tory aperture behind the right tentacle. Back keeled, without caudal gland and mucous orifice. L. ugrestis L., L. cinerevs 0. Fr. Mull. Fam. Helicidae. Sued/tea amphibia Drap., Pupa mi/xcorum L., Clavxiliu bidens Drap., Sulimus monta- nvs Drap., Helix pomatia L. (Roman snail), If. nemoralis FIR. Order 4. — OPISTHOBRANCHIATA.* Hermaph
. Elementary text-book of zoology. Zoology. 52 MOLLUSCA. keel, with caudal gland and mucous aperture at end of body. A. cmpiricorii m Fer., Umax L. Respiratory aperture behind the middle of the right edge of the mantle. Sexual opening far removed from respira- tory aperture behind the right tentacle. Back keeled, without caudal gland and mucous orifice. L. ugrestis L., L. cinerevs 0. Fr. Mull. Fam. Helicidae. Sued/tea amphibia Drap., Pupa mi/xcorum L., Clavxiliu bidens Drap., Sulimus monta- nvs Drap., Helix pomatia L. (Roman snail), If. nemoralis FIR. Order 4. — OPISTHOBRANCHIATA.* Hermaphrodite Gastropods, with fiat foot. Branchial veins open into the auricle behind the ventricle. The great majority of this order are without a shell. The branchial cavity never contains 523. —Dons (AcantJio- diris) piiosa (Bronn). Br, more than one gill. The gills are usually gins; 4, anus; F, tentacle. expoged (fig 533) or absent_ Sometimes there are dorsal processes, into which appendages of the alimentary canal enter (fig. 525). The nervous system contains cerebral, visceral and pedal ganglia (except in Tethys, which has a fused ganglionic mass and simple oesopha- geal commissure). The branchial veins, with a few exceptions (Gastropteron), enter the heart from behind. Sub-order 1. Tectibranchiata. Gill al- most always on the right side, covered by the mantle edge or placed in a dorsal branchial cavity. Shell usually present (fig. 524). Fain. Pleurobranchidse. With large gill on right side, and usually internal shell. Pleurobranchaa Jfcrftelii Cuv., Ph'iirobrancltus aurantiacus Cuv., Umbrella medlterranea Lam. Fam. Aplysiadae (Sea-hares). Shell covered by two lobes of the foot. Aplysia depilans L., Mediterranean. Farn. Bullidae. Bulla ampulla L., Philine apcrta L., Acer a bullata 0. Fr. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectzoology, bookyear1884
