III. The skull of ichthyosaurus, studied in serial sections

Abstract

Over two centuries have elapsed since the remains of this strange Mesozoic analogue of the Dolphin first began to attract attention and at least a century since they became the subject of serious scientific investigation, yet many points in the anatomy of the fossil still remain obscure, especially in the region of the head; and it was to elucidate these, that the present study, based on serial sections, was undertaken. A remarkably well-preserved skull in our University Collection provided excellent material (text-fig. 1). It bore the label Ichthyosaurus communis (but does not, I think, belong to that species) and was obtained from the Lower Lias of Lyme Regis. At some time or other it had been broken by clean fractures into four pieces, which had afterwards been cleverly cemented together so as to form an almost complete skull, the only parts missing being the supratemporal and articular bones, and two fragments of each of the lower jaws.