OCR Text |
Show 424 MR. G. A. BOULENGER ON A NEW [Mar. 15, anterior portion of which is broken away), the two intermediate teeth, with between them the diminutive tooth which had up to now escaped the describers of " Sorex pusillus," and the anterior true molar. The diminutive tooth in question is slightly larger than the additional tooth occupying the same position in the recent Myosorex varius. So long as more fossil forms are unknown, the homologies of these intermediate teeth will remain doubtful ; the diminutive one is presumably the homologue of the tooth which M. F. Woodward found as a vanishing structure in an embryo of Sorex (sp. ?), and which he considered to be the third lower permanent incisor *. Mr. G. A. Boulenger, F.R.S., exhibited a remarkable Ichthyo-saurian right anterior paddle (text-fig. 83) from the neighbourhood of Bath, which he had received from Mr. H. E. Lansdown, of Bath. The locality and horizon of the specimen, which had been in the possession of the late Miss Mary Ashley, were unknown. Text-fig. 83. Bight anterior limb of A. Mixosaurus cornalianus (after Kepossi); JB. Ichthyosaurus communis (after Lydekker); C. Ichthyosaurus extremus. In having three facets to the distal extremity, the humerus of this specimen, had it been found isolated, would have suggested Ophthalmosaurus (from which Baptanodon can hardly be separated on the evidence available at present) ; but, as shown by Seeley, the three facets of the Ophthalmosaurus humerus are for articulation with the radius, the ulna, and an ulnar sesamoid bone Proc. Zool. Soc. London, 1896, p. 569. |