. A manual of zoology. Zoology. III. CRINOIDEA 299 the ambulacral grooves are closed, and the ambulacra, which lack sucking discs, are tactile, locomotion being effected by the snake-like motion of the arms. The madreporite is on the ventral surface. Also on the ven- tral surface are five slits which con- nect with as many hurscr, thin-walled respiratory sacs into which the sexual organs open. The gonads are at- tached to a genital rhachis which coils through the In many brittle stars, especially in young specimens, there is a kind of asexual generation (schizogony), the animal dividing
. A manual of zoology. Zoology. III. CRINOIDEA 299 the ambulacral grooves are closed, and the ambulacra, which lack sucking discs, are tactile, locomotion being effected by the snake-like motion of the arms. The madreporite is on the ventral surface. Also on the ven- tral surface are five slits which con- nect with as many hurscr, thin-walled respiratory sacs into which the sexual organs open. The gonads are at- tached to a genital rhachis which coils through the In many brittle stars, especially in young specimens, there is a kind of asexual generation (schizogony), the animal dividing through the disc, the halves regenerating the missing parts. , arms unbranched (Ophio- pholis* (fig. 292), Ophioglvpha* Amphiura*); , the arms branched (Astrophyion,* fig. 293). Fig. 291.—Section of Ophiuroid arm (orig.). a, ambulacrum; 6, blood- vessel; c, ccelom; m, muscles of arm; n, nerve; r, radial water lube; v, 'ver- tebra' (coalesced ainbulacral plates).. 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 perfectly resemble the original Hertwig, Richard, 1850-1937; Kingsley, J. S. (John Sterling), 1854-1929, ed. and tr. New York, H. Holt
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectzoology, bookyear1912
