15Y H. H. SCOTT AND CLIVE E. Lor.D. 27 



and a-9 the pre-frontals at times (as we will deal with in a 

 later paper) coalesce with the nasals, it is wise to call these 

 bones — so marvelloush' reduced in size — yre-franio nasals. 

 In onr skull of Zipli'nis rar/msfris the prc-f rentals do not 

 reach the nasal bosses by an interval of 30 mm. in the 

 medium line, a condition of things always found bridged 

 in dolphins' skulls by cartilage "*''', until late in life, after 

 which ossification takes place. A glance at the Tasmanian 

 skull is enough to show that a cartilaginous bridge existed 

 there also, but was lost by cleaning and bleaching. 



This note of immaturity in our skull takes us natur- 

 ally to another point, viz.. the non-ossification of the 

 ethmo-vomerine cartilage, which apparently is also de- 

 pendent upon age factors, and not sexual ones. Culling a 

 note from the human subject, we find that the ossifii- 

 centre that gives rise to the ethmo-vomerinc cartilage (as 

 far as it is touched by ossification), the nlsfft f/aHi, and 

 the cribriform plate does not complete its activities luitil 

 half the period of adolescence has been passed. In whales, 

 the sense of smell has atrophied, and the ossific powei-s of 

 the centre named turns its activities upon the ethmo- 

 vomerine cartilage — in the ziphoid whale;i — but appar- 

 ently not till late in life. In most of the Dtl pltiiiitln the 

 cartilage remains as j.uch throughout life, but in very old 

 dolphins it may manifest some ossification at its proximal 

 end. 



This question of the reduction of the senses in whales 

 is one of the things that warrants considerable attention 

 bc>ing paid to it. if we are to unravel the complexities that 

 surround the group origins of the Cetarfa as a whole. 

 Brietly it may be said in passing that the retention of the 

 nasal organs in whales cuts them off from dolphins, and 

 that the Zi i>hii(hf', to some extent, are midway between 

 them. To bring our specimen into line with the ten ziphoid 

 skulls that True listed, and monographed, we will here 

 quote the description of the specimen that comes nearest 

 to our own, viz., his specimen No. 20971. Thi-s was the 

 skull of a female whale that was captured at Barnegat, 

 New Jersey, U.S.A. Of this True says: — "Adult female. 

 " Majority of sutures open, but those on superior surface 

 " of rostiiim between maxillse and pre-maxilla; jjartly anky- 

 " losed. Vomer nearly all ankylosed to rostral portion of 

 '■ pre-maxillae. It presents a slight median elevation, but 

 " there is na mesirostral nssifiraf/oii. Right pre-maxillfe 

 " in front of nares flat and horizontal ; left, nearly .so, but 

 "with a quite broad longitudinal groove. Opposite maxil- 



(8b) We have evidence as to the origin of this cartilage, and shall 

 in due course deal with the same. 



