Lectures on the comparative anatomy and physiology of the invertebrate animals : delivered at the Royal College of Surgeons . gth, slightly en-larged at one outer tunic or capsuleis elastic and transparent: this contains an elongated sac, occupyingthe larger extremity of the sheath, and filled with the minute clavatespermatozoa. This sperm-sac communicates by a short narrow canalor isthmus, with a second narrower, elongated sheath, inclosing ahighly-elastic piston, from which a spiral filament is continued to thesmall extremity of the outer sheath. In the Cuttle-fish, the isthm
Lectures on the comparative anatomy and physiology of the invertebrate animals : delivered at the Royal College of Surgeons . gth, slightly en-larged at one outer tunic or capsuleis elastic and transparent: this contains an elongated sac, occupyingthe larger extremity of the sheath, and filled with the minute clavatespermatozoa. This sperm-sac communicates by a short narrow canalor isthmus, with a second narrower, elongated sheath, inclosing ahighly-elastic piston, from which a spiral filament is continued to thesmall extremity of the outer sheath. In the Cuttle-fish, the isthmusconnecting the sperm-sac with the ejaculatory sac is longer, and thecoils of the spiral membrane are closer and more numerous. Thespermatophores of the Calamary are remarkable for the superior sizeand length of the internal sac containing the spermatozoa. Underevery modification, the analogy of the apparatus which forms thereceptacle of the essential particles of the fertilising fluid, with thenidamental sacs containing the ova in the opposite sex, is veryobvious. The spermatophores in the bursa are regularly arranged. Male organs, Octopus. * CCCLXXVIII. t CCXXXIII. s s 3 630 LECTURE XXIV. in superimposed longitudinal layers: their anterior ends directedforwards, their opposite ends often bound together by interlacedfilaments. The movements of the spermatophores, when liberatedfrom the sac, are truly remarkable: the smaller extremity of theouter capsule, to which the spiral spring is attached, protrudes by akind of inversion, and the inner spermatic sac is drawn forwards;the action is repeated until the ejaculatory sac is extended from thesheath, when there is a slight cessation of movement. It then re-commences ; the sperm-sac is compressed and protruded farther ; theisthmus gives way, and the spermatozoa are violently expelled, bothoutwards and into the cavity of the external sheath. The efficientcause of the movements appears to be a combination of the contrac-tility of th
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Keywords: ., bookauthorowenrichard18041892, bookcentury1800, bookdecade1850
