' BY H. H. SCOTT AND CLIVE E. LOED. 103; 



5. If they fuse, they may do so either most strongly 

 to the frontal, or similarly to the pre-frontal. 

 Again, the whole mass at the vertex may fuse to 

 extinction, and the ethmo-turbinals remain as 

 cartilage. 

 The latter state is nearest to the skull of Ziphius 

 cavirostris, as represented in the Hobart Museum Osteolo- 

 gical collection. By the usual methods adopted in cleaning 

 Museum cetacean crania, eitJier this region of a Dolphin's 

 skull is left, immersed in muscle and cartilage, or else it 

 is so mutilated in the attempt to remove such animal mat- 

 ter, that it is useless to a student. Our notes are made 

 from skulls that took at least two years to prepare, every 

 microscopic fragment of bony tissue being retained in 

 position, and every microscopic fragment of animal matter 

 having been removed by isolated maceration, thus avoid- 

 ing a chance blow from o^:her bones. In this way only 

 is it nossible tn retain spongy bone, and to d'^^^■no the 

 bounding lines of ostotic action. Beach worn specimens 

 often help to elucidate a point, here and there, better 

 than imperfectly macerated ones, but it is sure, to happen 

 that the very TDiece most urgently needed has been ground 

 away. 



To correctly work out all these points it is essential 

 to disarticulate a young Tursiops skull, and trace the re- 

 spective elements into the cranial cavity, and unless the 

 fronto-occipital sutures are carefully separated, some of 

 the evidence will be lost. 



Phylogenetically, all this means that the ancestor of 

 the Dolphin group manifested well-developed ethmoidaJ 

 senss capsules, the ossific processes relating to which were 

 arrested. A cartilaginous remoulding took place, and 

 later on a partial ossification of some parts, with a tend- 

 ency to reproduce others, in a state similar to that of the- 

 Wormian ossicles of human crania. We close these 

 notes as we began them, by saying these are not vestiges 

 of the cartilaginous cranium. 



TUESIOPS TURSIO. 



Southern Form. 



The males of this genus closely approach the size at- 

 tained by the females of the genus GJohicepho.his. and', al- 

 though the maximum size has still to be recorded, it is 

 certain that they reach eleven feet. The females, in our 

 opinion, never exceed ten, the vast majority being a full 

 foot shorter. 



