Hector. — Xotes on the Whalea of the New Zealand Seas. 343 



Bueuos Ayres, haviug been described in detail by Burmeister as Ejdodon 

 australe. 



In European museums this whale is only represented by skulls, the 

 individual specimens of which have generally been distinguished by specific 

 and even generic appellations ; but it has been shown by Prof. Turner, of 

 Edinburgh University, in a memoir reviewing the whole subject,* that the 

 distinctions are only founded on changes and developments of the meso- 

 ethmoid cartilage, which with increasing age becomes ossified and swollen 

 into different shax^es, while at the same time the bony processes surrounding 

 the prte-nasal fossa also undergo change of form ; but these differences he 

 considers do not exceed the range of individual variation which is often 

 met with in comparing a series of crania of the same species of animal. 



He further shows that the geographical range of Zijyhiiis cavirostris, 

 including aU known forms, is equal to that of the sperm whale, of which 

 one species only is now generally admitted to exist. 



The specific distinction made by Dr. von Haast between the Chatham 

 Island and New Zealand specimens is founded on little more than the form 

 of the teeth, which in the latter specimen, now in the Canterbury Museum, 

 I have formerly pointed out had become absorbed,! only the fangs being left, 

 while in the slightly smaller and probably younger specimen from the 

 Chatham Islands the teeth were still large and serviceable,! but such 

 degeneration of the dental apparatus with advancing jeshvs is surely not to 

 be taken as a character of specific value. 



The only important difference between the descriptions of Dr. von Haast 

 and Burmeister is the presence of one pair of ribs less in the New 

 Zealand skeleton ; but this is so violent a departure fi'om the number 

 obtaining in a so closely allied, even if not an identical species, and from 

 the number found in all other ziphioids exce]Dt Hyperoodon, that it should, 

 I think, be attributed to individual abnormality or an accident to the 

 preparation. 



One important feature in Burmeister' s description has not been alluded 

 to by Dr. von Haast, namely, the presence not only of the large terminal 

 mandibular teeth, but also thu^ty small teeth in the gum of the mandible and 

 twenty-five on each side in the gum of the upper jaw. As the Buenos Ayres 

 specimen was quite young, measuring only 13 feet in length, whereas 

 the Canterbury specimen was adult, and measured 29 feet, the absence 

 of the functionless teeth in the latter was probably due to the difference 

 of age. This is clearly opposed to the generic value attributed to such 

 organs in the case of Oulodon. 



* Trans. Eoy. Soc. Edin., XXVI., 759. 

 t Trans. N.Z. Institute, V., 166. J Trans. N.Z. Inst., V., pi. 4 and 5. 



