266 DISCOVERY REPORTS 



15. Dorsal fin, length of base. This is a rather unsatisfactory measurement as it is 

 very difficuh, especially in the case of Blue whales, to say where the anterior part of 

 the fin begins. 



16. Flipper, tip to axilla. The axilla is taken as the most anterior point on the dorsal 

 rim of the flipper. 



17. Flipper, tip to anterior end of lower border. 



18. Flipper, length along curve of lower border. Taken with the preceding measure- 

 ment this gives the relative curvature of the flipper. 



19. Flipper, greatest width. 



20. Severed head, condyle to tip. 



21. Skull, greatest width. This is not a very reliable measurement and can usually 

 be taken only indirectly. The width of the head is measured from eye to eye, and that 

 of the skull is determined by feeling for the bone behind the eye with the point of a knife. 



22. Skidl length, condyle to tip ofpremaxiUa. To take this measurement it is necessary 

 to cut down the tip of the snout until the premaxilla is found. 



23. Flipper, tip to head of humerus. The head of the humerus is not often accessible, 

 so that it is difficult to take this measurement systematically. 



24. Tail, depth at dorsal fin. This is taken in a straight line from a point opposite 

 the base of the dorsal fin. 



25. Flukes, notch to tip. As the flukes are always cut off at sea this can only be taken 

 in the case of foetuses. 



26. Flukes, total spread. Taken only in the case of foetuses for the same reason. 

 Only measurements i to 16 can be taken when the whale is first drawn up. The rest 



are taken later on as opportunity permits. 



Notes are made on the external characters as follows : 



I. Colour. Routine notes are made only on features which are subject to variations. 

 In Blue whales observations are made on such points as the number of white flecks 

 over the posterior part of the ventral grooves, the size and degree of differentiation of 

 the spots of pale colour over the back and flanks, the striations on the ventral surface 

 of the tail flukes, etc. Among Fin whales there is some variation to be noted in the 

 degree to which the dark pigment extends over the ventral surface, of which the greater 

 part is white. In some also the dorsal pigment is lighter than in others. 



2. Baleen. In the case of a large number of whales the number of baleen plates 

 has been counted, and in still more cases the longest plates have been measured from 

 base to tip. The spacing of the plates has also been measured. It does not appear, 

 however, that these routine observations on the baleen lead to any very useful results, 

 though measurement of the length of the plates in young whales has some bearing on 

 the study of the whale's growth and feeding. 



3. Hair. The hair which occurs on the mandibles and snout is subject to some 

 variation, and routine notes as to the numbers and disposition of the hairs were made 

 for some time. It does not appear, however, that diff'erences were more than individual 

 variations. 



