. A manual of zoology. Zoology. 2S4 ccelhel:mixthes oriL;in of these vessels from the calom the followhig points are in favor, (i) The \"entral eord is enclosed in the \"entrai blood sinus; (^j) the llagellale funnels, just alluded to, lie in the blood laeun;e. ustially in ampullar spaces between the ventral and lateral blood sinuses. Further relations are shown by Aiaulliolhicila ptii'Jiiij. parasitic on fishes. This has both blood-vessels of the oliL;och:rtcs, a bodv cavity di\ided by septa, and cha'ta-. On tlie other hand, it is leechlike in other features; two suckers and
. A manual of zoology. Zoology. 2S4 ccelhel:mixthes oriL;in of these vessels from the calom the followhig points are in favor, (i) The \"entral eord is enclosed in the \"entrai blood sinus; (^j) the llagellale funnels, just alluded to, lie in the blood laeun;e. ustially in ampullar spaces between the ventral and lateral blood sinuses. Further relations are shown by Aiaulliolhicila ptii'Jiiij. parasitic on fishes. This has both blood-vessels of the oliL;och:rtcs, a bodv cavity di\ided by septa, and cha'ta-. On tlie other hand, it is leechlike in other features; two suckers and apparatus on the Hirudinean piattern. Braiu-iiiobJcUa, parasitic on the gills of the cravfish, is a cha"'topod devoid of bristles and furnished with a sucker in correlation with its habits. Order I. Gnathobdellidse. The ja^yed leeches include Hiriido iiicdicinaUs, once extensivelv used for blooddetting, now little employed. Ha-madipsa includes land leeches of the tropics. KcpJicUs* soft jaws. MacyobdcUa''* includes oitr largest species. Order II. Rhynchobdellidffi. \A'lthout jaws. mostlv feed on snails and fishes. Clcpsinc* Hirmcnlaria ghilijiii of South America is poisonous. ,* cylindrical, occur in salt and fresh water, parasitic on fishes. Ichthyobdella,* Ponlohdi'lla,'" marine; Piscicola, fresh water. Class IV. Polyzoa (Bryozoa). In external appearance the Polyzoa closely resemble the hydroids, so diat the inexperienced have dilticulty in distiti- guishing them. Like them by budding thev form colotiies which are either incrusting sheets or assume a more bush-hke character. Further they have a crown of ciliated tentacles which can be spread out or quickly retracted. In internal characters tlie two groups are greatly difierent. The Polyzoa ha^•e a complete aUmentary canal, with its three divisions, wliich is bent upon itself so that the anus has near the mouth. The central ner^•ous s}'stem lies be- tween mouth and anus, and the sing
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectzoology, bookyear1912
