W. T. CALMAN. 



end of segment. Antennal scale with outer margin straight, or, in smaller specimens, 

 concave. Third maxillipeds extending to or slightly beyond end of scale. First 

 legs extending a little beyond middle of terminal segment of third maxillipeds ; 

 hand from nearly four to nearly five times as long as broad, terminal tooth of palmar 

 edge at about one-fourth of the length of the hand from distal end. Last pair of 

 legs extending forward to the tip of the antennal scale. Endopod of first pleopod 

 articulating with distal inner angle of peduncle. 



Branchial system. — Five pleurobranchiee on each side, on the last five thoracic 

 somites ; no arthro- or podo-branchise. 



liemarks.—The ' Discovery ' specimens differ from Dr. Pfeffer's description, and 

 from a co-typical specimen with which I have compared them, in the more slender 

 form of the body, due especially to the greater length of the sixth abdominal somite ; 

 in the greater length of the rostrum ; in the shorter lobe on the basal segment of the 

 antennule, reaching only to about the distal third of the segment, while in the typical 

 form it reaches nearly to the end ; and in the narrower " hand " of the first legs. 

 But while each of the three well-preserved specimens in this collection differs from 

 the co-type in all these points, they do so in varying degree. The differences are at 

 least as important as s(mie of those which have been regarded as of specific value by 

 recent writers on the Crangonida^, but I do not think that they would justify us, at 

 present, in separating the form inhabiting the area explored by the ' Discovery ' from 

 that found in the very distant region of South Georgia. 



The following table gives some measurements, in millimetres, of the co-type of 

 C. antarcticus as compared with the three most perfect specimens in the ' Discovery ' 

 collection. All the specimens appear to be females or immature males. 



Dr. Pfetfer * was the first to draw attention to the apparent " bipolarity " in the 

 distribution of the genus Crangon. With the exception of the very imperfectly 

 known C. capensis, Stimpson, from the Cape of Good Hope, C. antarcticus is the only 

 species of the genus inhabiting the Southern Hemisphere, and is widely separated from 

 all the other species, which are confiiied to the temperate and (if Sclerocrangon be 



* Die niedere Tliierwelt des antarctischen Ufergebietes. Intornat. Polarf. Deutsch. Exited., ii. (1890), 

 pp. 520-572. 



