. The anatomy of the common squid, Loligo pealii, Lesueur. Squids; Mollusks. %'6 from the cup by the inpushed base and "piston", while when the arm is withdrawn, they hold by suction, often, until the pedicle breaks. Argonauta and other Octopoda have one of the arms transformed into a sac, which, after receiving the spermatophores, is detached and placed in the mantle cavity of the female. This modified arm is called the Hectocotylus. The Decapoda have one or more rarely two of their arms slightly modified or "hectocotylized". In Lohgo (Plate III, Pig. 18) the left fifth ar
. The anatomy of the common squid, Loligo pealii, Lesueur. Squids; Mollusks. %'6 from the cup by the inpushed base and "piston", while when the arm is withdrawn, they hold by suction, often, until the pedicle breaks. Argonauta and other Octopoda have one of the arms transformed into a sac, which, after receiving the spermatophores, is detached and placed in the mantle cavity of the female. This modified arm is called the Hectocotylus. The Decapoda have one or more rarely two of their arms slightly modified or "hectocotylized". In Lohgo (Plate III, Pig. 18) the left fifth arm is hectocotylized. Some ten or twelve suckers on each side of the tip of the arm have their pedicles enlarged and their cups reduced, the pedicles becoming large blunt cones bearing minute cups or near the end of the arm both stalk and sucker are reduced. The inner row of suckers is less modified than the outer. The portion of the arm between the two rows of enlarged pedicles forms a rounded ridge as high as the pedicle. The hectocotylus probably represents the vestige of a functional structure of an ancestral form. It is barely possible that the arm may be used for the transference of spermatophores. The siphon or funnel (text figure 10) developes from two pairs of ridges which appear upon the posterior surface of the embryo. The hinder pair appears between the mantle and the eye, and forms the siphonal valves which will be described later. The anterior pair lies below the gills and anus and between them and the arms. The latter ridges become elevated and incurved until their edges meet and unite, thus forming a conical tube, the siphon, which leads from the mantle cavity to the exterior. This muscular tube is attached dorsally by a pair of large muscles, the siphonal retractors. Each siphonal retractor is a strong rounded muscle which, arising from the side of the ventral end of the vane of the pen, passes obliquely downward and forward in a depression between the liver abo
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectmollusks, bookyear191
