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Show 634 PROF. FLOWER ON A TWO-HORNED RHINOCEROS. [June 4, Prof. Ray Lankester, M.A., F.R.S., read a memoir on the hearts of Ceratodus, Protopterus, and Chimeera. The structure of the conus arteriosus and its valves was more particularly described in this paper. Owen and Hyrtl had shown that the conus of the Dipnoans differed from that of cartilaginous fishes and Amphibians in the fact that its walls were devoid of pocket-valves, and presented instead a long spiral valve and a second short vertical valve. Dr. Gunther, the only author who had described the heart of Ceratodus, showed that it possessed in the upper part of the arterial cone pocket-valves, whilst the spiral valve was shortened so as to be absent from this upper region. The possession of pocket-valves served as a very important character to connect the Dipnoans and the other fishes. Prof. Lankester now showed that in the lower part also of the arterial cone of Ceratodus there were numerous small pocket-valves, in addition to those in its upper part; and further he showed that these small pocket-valves (so called "ganoid valves") were also present in the lower part of the arterial cone of Protopterus, the African Mud-fish, which had been generally supposed to be quite devoid of this kind of valve. The basal fibro-cartilage of the floor of the heart was described and compared in Ceratodus and Protopterus, and a possible rudiment of this remarkable structure pointed out in Ceratodus. This Paper will be published entire, with illustrations, in the Society's ' Transactions.' The following papers were read :- 1. On the Skull of a Rhinoceros (R. lasiotis, Scl.?) from India. By WILLIAM HENRY FLOWER, F.R.S., V.P.Z.S. [Received October 12, 1877.] Mr. Sclater has put into m y hands for examination the skull of a Rhinoceros, which he had received from Dr. W . D. Stewart, of Cut-tack, Orissa, being the skull of the two-horned Rhinoceros killed near Comillah, in Tipperah, as mentioned in P. Z. S. 1877, p. 269. Mr. Sclater thinks that the skull may not improbably belong to the species (at present only known by the living animal in the Society's menagerie) which he has named R. lasiotis. It is that of a nearly adult animal. All the sutures of the upper surface of the cranium are consolidated ; and all the permanent teeth in both jaws are in place except the posterior molars, which are still concealed in their alveoli. In size and general conformation it resembles the skull of R. sumatrensis, and possesses all the essential characters * which distinguish that species from R. indicus and B. sondaicus, viz. the separation of the postglenoid from the posttympanic processes of the squamosal below the auditory meatus, the backward position of the occipital crest (though, perhaps, less marked than usual), and the 1 See " O n some Cranial and Dental Characters of the existing Species of Rhinoceros;' P. Z. S. 1876, p. 443. |