. Land snails from Hawaii, Christmas island, and Samoa. Snails; Mollusks; Mollusks; Mollusks. 48 Bernice P. Bishop Museum—Bitllctin 47 Group F As well-developed embryos of Achatinella viridans have three whorls the next stage examined (fig. 22, a) was evidently the youngest phase of the ananeanic, the shells having 3 to 3 1/4 whorls. The genitalia were minute and translucent, the uterus being almost transparent and also quite frail (two specimens breaking in the process of dissection at this point before a whole one could be obtained). The appendix was absent, and the penis had an enlarged tip
. Land snails from Hawaii, Christmas island, and Samoa. Snails; Mollusks; Mollusks; Mollusks. 48 Bernice P. Bishop Museum—Bitllctin 47 Group F As well-developed embryos of Achatinella viridans have three whorls the next stage examined (fig. 22, a) was evidently the youngest phase of the ananeanic, the shells having 3 to 3 1/4 whorls. The genitalia were minute and translucent, the uterus being almost transparent and also quite frail (two specimens breaking in the process of dissection at this point before a whole one could be obtained). The appendix was absent, and the penis had an enlarged tip, from which extended its retractor muscle as the finest of threads. Spermatheca duct and vas deferens had not developed, as the uterus appeared to be an unaccompanied tube. The part that would have developed into the prostate gland was not even enlarged, an angle at the tip of the uterus on one end and the narrower tube of the hermaphrodite duct on the other showing its position. It was embedded in soft clinging mate- rial, which it was necessary to remove before the outline of the tube could be seen. The uterus lay in the same position as at maturity and at its proximal end the oviduct was attached by a wide base to the wall of the animal behind the right tentacle, at the place where the genital orifice would later develop. p-^S- Figure 22.—Achatinella viridans Mighels (No. 87428) : a, genitalia, ananeanic stage, with details, lettering as in figure 17, ped. r. = pedal retractor, r. t. r. = right tentacular retractor; b, showing position of genitalia in specimen of same size as that shown in figure 21, t. = tentacle. At this stage an important feature was a connection near the base of the penis. It led from there shortly but indirectly to the right cerebral ganglion, being a thread-like nerve in a wide filmy sheath, which may also have served to conduct arteries in this region. The connection was noted in all the other five groups, but it grew constantly looser and
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Keywords: ., bookauthorp, bookcentury1900, bookdecade1920, booksubjectmollusks
