Miscellaneous. 183 Kojia Floweri, from Mazatlan, Lower California — described from a specimen consisting of the front of a lower jaw, and from the figure and notice of the animal, measnring nine feet in length, recently for-warded to him by Colonel Gi'ayson. It is very interesting as proving that this genus is found in the Xorth Pacific. The account and figure of Dr. GiU are so very like that oi Kogia MacLeai/i that I should not bo at all surprised if Eogia hreviceps from the Cape of Good Hope, Kogia MdcLecojii from Australia (which has been proved not to be distinct fi-om the skull of Fhyseter simus from the east coast of India), and Kogia Floicen from ICazatlan are all the same species, naturally inhabiting, like the sperm-whale, the tropical regions and wandering to the north and south, as the same species has been found on both sides of the equator. From the comparison of the photographs which Mr. Krefi't sent me, with the skull from Madras (described by Professor Owen) in the British Museum, I could find no difference, as stated in the ' Cata-logue of Seals and M'hales in the British Museum.' ISTJG, p. 392 ; and the comparison of the skulls since sent by Mr. Krefft has established the identity of the Australian specimens from the south and Indian from the north of the equator. Dr. Gill, having over-looked this observation (published in 1866), observes that a generic name will sooner or later be desired for Eogia simus from Madi-as, and therefore proposes to caU it Calligiuithus simus (p. 738) — and copies Owen's figure of the young skull (p. 741, figs. 168-171), which is not to be confounded with the skeleton that Professor Owen cojiies from KrefFt's photograph of Euphysetes Grayii, quite a distinct whale of the same group. On^ihe Development of the Phragmostracum of the Cephalopoda, and on the Zoological Relations of tin Ammonites to the Spirulae. By M. Mcnier-Chalmas. I have the honour to submit to the Academy the results of the observations which I have made on the development of the phrag-mostracum of the Cephalopoda in the laboratory of paljeontological research at the Sorbonne, under the guidance of M. Hebert. This comparative embryogenic investigation proves very clearly that the Ammonites are not tetrabranchiate Cephalopoda allied to the Nautili, as is generally supposed, but dibranchiate decapod Cephalopoda, having the greatest affinity to the Spirulce. As early as 1867 M. J. Barrandc had proved, in his great work on the Silurian system of Central Bohemia, the small resemblance that exists between the Goniatites and the XautilidiB during the first period of their development. In fact, the initial chamber of the phragmostracum of the Cephalopoda of the Nautilide group, except as regards the external cicatrix, does not sensibly differ in its general organization from the other primary chambers which arc developed a little later. In speaking of Cyrtocrnis il. Barrande moreover expresses himself as follows : — '• We shall also call attention to the
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