. Elementary text-book of zoology, general part and special part: protozoa to insecta. Animals. Fig. 377.— PentaMnmum dentieulafitm. Young form of P. IrBn'ohift. O, Mouth; llf, tlip four liooks; D, intes- tine : A, anus. the anterior appendages, are lost in the course of development. The nervous system is confined to a simple subcesophageal nervous mass, with oesophageal ring and giving off numerous ner- vous trunks. Eyes and organs of respiration and circulation are wanting. The alimentary tract is a simple canal in the middle of the body, which opens by an anus at the posterior end. Special
. Elementary text-book of zoology, general part and special part: protozoa to insecta. Animals. Fig. 377.— PentaMnmum dentieulafitm. Young form of P. IrBn'ohift. O, Mouth; llf, tlip four liooks; D, intes- tine : A, anus. the anterior appendages, are lost in the course of development. The nervous system is confined to a simple subcesophageal nervous mass, with oesophageal ring and giving off numerous ner- vous trunks. Eyes and organs of respiration and circulation are wanting. The alimentary tract is a simple canal in the middle of the body, which opens by an anus at the posterior end. Special cutaneous glands are present in great numbers and strongly developed. Male and female are distinguished by considerable diflferences in size and by the difterent position of the genital openings. \^'hile the genita opening of the surprisingly small male lies not far behind the mouth, that of the female is situ- ated near the anus, at the hinder end of the body. The Linguatulida, when sexually adult, in- habit the air chambers of Avarm-blooded animals and Amjihihia. The developmental history of Pentastomum tcenioides, which lives in the nasal cavities and in the frontal sinuses of dogs and wolves, is known from the researches of Leuck- art. The embryos of this species, while still enveloped in the egg-membranes, pass out the nasal mucus on to plants, and thence into the stomach of Rabbits and Hares, moi-e rarely into that of Man. When freed from the egg- membranes, they pierce the walls of the in-. Fio. 378.—Young fonna of PcnliKlommn tcenioides (lifter R. Leuckart). a. Egg with embryo. 6, KiHbryo with two pairs of hooked feet, Ilf and ///"'. c. Larva from liver of rabbit. O, Ganglion ; D, intestine ; lid, skin glands, d, Older larva. ~ - - «. g'ands. O, mouth ; A, anus; Gd,. 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 perfe
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectanimals, bookyear1892
