. Discovery reports. Discovery (Ship); Scientific expeditions; Ocean; Antarctica; Falkland Islands. SYSTEMATIC REPORT 41 Remarks. Characters used by M. Sars (1857) to define Lophogaster typicus have proved to be variable and unreliable. Fage (1942, pp. 7-39), in a survey of all the known material of the species, divided it into four distinct species: (1) typicus (for the forms from the northern hemisphere); (2) challengeri (for specimens collected by ' Challenger' in South African waters and described by G. O. Sars as typicus—the new specific name emphasizes the fact that these specimens are t
. Discovery reports. Discovery (Ship); Scientific expeditions; Ocean; Antarctica; Falkland Islands. SYSTEMATIC REPORT 41 Remarks. Characters used by M. Sars (1857) to define Lophogaster typicus have proved to be variable and unreliable. Fage (1942, pp. 7-39), in a survey of all the known material of the species, divided it into four distinct species: (1) typicus (for the forms from the northern hemisphere); (2) challengeri (for specimens collected by ' Challenger' in South African waters and described by G. O. Sars as typicus—the new specific name emphasizes the fact that these specimens are the true types of challengeri); (3) pacificus and (4) hazvaiiensis. Fage separated his four species on the following four salient characters of the carapace: (1) the tuberculation of the integument, (2) the presence or absence of a post-orbital spine, (3) the shape of the profile (in lateral view) of the dorsal margin of the free postero-lateral regions or' wings', and (4) the size and angle of the postero-lateral spine. He showed, moreover, that these characters were corre- lated with geographical distribution and conditions of the habitat. At first sight it may seem that these characters are too trivial to warrant the separation of challengeri from typicus, but examination side by side of specimens from the northern and southern hemispheres leaves no doubt that they do represent two different species and I have no hesitation in accepting challengeri as Fig. 2. Lophogaster challengeri Fage. A, anterior end in dorsal view, x 10; B, lateral view of postero-lateral region of carapace ('wing'); C, telson and right uropod in dorsal view, x 10; D, distal end of telson (enlarged), x 19. Iww*.. Sh«-. 9 The integument of the carapace, especially in the mid-dorsal area, is covered with more or less well-developed tubercles in both typicus and challengeri. This condition is much more pronounced in juveniles and as growth proceeds the tubercles tend to disappear. In the Discover
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