_Argonauta_ has a lachrymal pore before and beneath the eye. The beautiful and obvious respiratory mechanism in the Cephalopoda needs not to be described. There is a large sac behind the viscera of the Argonaut, which opens on each side; it is perhaps of some hydrostatic use. There are at least three pairs of salivary glands, of which four open on the floor of the mouth, and two or three at the commencement of the gullet. Several small shells of Pteropoda and fragments of Cephalopods were found in the stomach, on which was observed the large nervous ganglion found in all these, as well as in lower mollusks. The branchial nerves have each two ganglia, of which the last at the root of the branchiæ is rounder than the other; the branchial hearts have processes as in _Sepia_. In _Sepia_ two openings lead from the respiratory sac into the cavity containing the venæ cavæ and their secreting appendages often imbued with glittering crystalline particles, and from the above cavities a wider opening on each side leads into a second sac further back, situated in front of the shell. There are auditory sacs in the Argonaut. The oviducts have separate openings, but originate together. Both _Sepia_ and _Argonauta_ are infested with a subcutaneous filiform entozoon, hooked anteriorly and rolled up spirally in the former. _Loligo media_ and _Sepiola_ have but one oviduct, and the two large, glandular, laminated organs, opening at their summits, are wanting in _Argonauta_ and _Octopus_. In _Sepiola_ one would almost think that copulation takes place, for the author has taken what he supposes to be the capsules of Needham, with dilated oval ends, tubular and bent pedicles or processes, enclosed elastic filaments, and adhering zoosperms, from the oviducts of the female: he has made the same observation also in _Sepia_. The latter has very similar male organs to _Octopus_, as described by Cuvier. In the embryo _Sepia_, the yelk enters below the mouth and opens into the upper stomach, but the beak of the animal also appears to be inserted into it behind. The vitellus in reality therefore enters by the foot, as it does in _Bulimus_, and probably in all Bivalves. * * * * * On the Linnean Manuscript of the 'Museum Ulricæ.' By SYLVANUS HANLEY, Esq., F.L.S. [Read Dec. 3, 1858.]