BY H. H. SCOTT AND CLIVE E. LORD. 27 



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

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

 bonesi — so marvellovisly reduced in size' — yre-fronto oiasah. 

 In onr skull of Ziphius caviiusf7-is the pre-frontals do not 

 reach the nasal bosses by an intei'val of 30 mm. in the 

 medium line, a condition of things always found bridged 

 in dolphins' skulls by cartilage ^^b)^ 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 ossific 

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

 far as it is touched by ossification), the crista r/alli, and 

 the cribriform plate does not complete its activities until 

 lialf the period of adqjescence has been passed. In whales, 

 the sense of smell has atrophied, and the ossific powers of 

 the centre named turns its activities upon the ethmo- 

 vomerine cartilage^ — in the ziphoicl whalesi — but appar- 

 ently not till late in life. In most of the Delphinidm the 

 cartilage remains as such throughout life, but in very old 

 •doiphins it may manifest some ossificatio-n at its proximal 

 end. 



This question of the reduction of the senses in whales 

 is one of the things that warrants considerable attention 

 being paid to it, if w© are to luiravel the complexities that 

 surround the group origins of the Geiacea as a whole. 

 Briefly it may be said in passing that the i-etention of the 

 nasal organs in whales cuts them <M from dolphins, and 

 thfit the Ziplnidce, 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. This 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 rostrum between maxillas and pre-maxillse partly anky- 

 " losed. Vomer nearly all ankylosed to rostral portion of 

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

 '■ there is no viesirostral ossification. Right pre-maxiillse 

 " 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. 



