48 DISCOVERY REPORTS 



Paracyamus boopis was found on all Humpbacks on which it was sought : the infection 

 is not usually very heavy. The parasites occurred in greatest numbers around the 

 genitalia, among the Cirripedes, and between the ventral grooves: they are scattered 

 over the rest of the body in lesser numbers. 



Patches of diatom film are recorded from only six Humpbacks, all from South Georgia: 

 in a further sixteen which were examined for film it was found to be absent. The patches 

 were not large and in no case formed a film covering all or most of the body. Patches 

 were noted on the head and jaw twice, on the tail and flukes three times, and on the back 

 once. In all cases the film consisted of Cocconeis wheeleri (Hart), a species first described 

 in 1935 and hitherto found only on Humpbacks, with occasionally a few Navicula sp. 

 There is only one note on this subject in the South African observations on Humpbacks, 

 and it records that diatom film, though searched for, was not present. Observations are 

 too few to establish any correlation between the presence of patches of film and the 

 fatness of the whale. A thick growth of Licmophora Lyngbyei was found on the shells of 

 Coronula infesting Humpbacks at South Georgia in nearly every case when it was 

 looked for. 



The ciliate protozoan Haematophagiis is recorded at South Georgia as present on the 

 baleen in eighteen whales and absent in six : it was not recorded from the South African 

 series, where it was definitely absent in one instance. 



Like other whales, the Humpback, while in temperate and tropical waters, is subject 

 to attack by some unknown predator, parasite or disease, which removes semi-ovoid 

 pieces of blubber from the body surface, making oval pits which slowly heal, leaving a 

 white or grey scar. Table XV gives the particulars about the pits or scars on those 

 Humpbacks in which their presence was noted. The most striking point of these ob- 

 servations is the low incidence of attack in this species in comparison with the other 

 rorquals, in which the skin is sometimes completely covered with scars, and in conse- 

 quence has a silvery grey appearance at a short distance. This is all the more remarkable 

 as the attack occurs in warmer seas, where the Humpbacks follow a leisurely migration 

 in coastal waters ; one can only surmise that the comparative immunity in this species 

 is correlated with its coast-frequenting habits, in contrast with the more offshore habits 

 of the swifter and more active rorquals. 



The table shows, as would be expected, that fewer pits and scars are found on the 

 smaller immature whales, but, as mentioned in a later section where the age attained by 

 Humpback whales is discussed, the presence of several ages of old scars is of little or no 

 help in showing the approximate age of individual whales. The occurrence of scars on 

 Humpbacks at South Georgia merely indicates, what is already known, that the whales 

 have migrated from lower latitudes. 



Lillie (191 5) noted the presence of open wounds on the Humpbacks at New Zealand, 

 and states that the whalers told him that the wounds were more numerous on the whales 

 during their southern migration, after their visit to more northern waters. 



