20 W. M. TATTERSALL. 



the total body-length. The meral joint extends beyond the tip of the antennular 

 peduncle, and is about one-tenth shorter than the combined lengths of the terminal 

 three joints, while the carpal joint is four times as long as the propodal. It will be 

 seen, therefore, that these changes during growth are quite considerable, "and most 

 evident in the elongation of the carpus. 



It was noted above that Sars' specimen, 13 mm. in length, had the elongate 

 limbs only as well developed as in a specimen 8 mm. long. I have found in the 

 present collection two specimens, 16 and 17 mm. long, in which these limbs were at 

 the same stage of development. They were accompanied by specimens with more 

 fully developed elongate limbs, and I would suggest that the comparative shortness 

 of these legs in the above-mentioned two specimens and in Sars' type is due to their 

 having at some earlier period been broken off and grown again. This is a common 

 occurrence in Decapods, and I should think is by no means rare in Euphausians, 

 especially those with elongate second legs, which must be specially liable to be 

 detached. The re-developed limb is usually shorter than the one it replaces. 

 I believe this explanation to be the correct one in. the present instance, though it may 

 be that we have here a case of retarded development. Further slight changes during 

 growth are seen in the proportional length of the last pleon segment, which in very 

 young specimens is slightly longer than the combined length of the preceding two, 

 while in full-grown specimens the reverse is seen, though the differences either way 

 are not great. 



The antennular peduncle is a little longer proportionally in full-grown specimens, 

 while the outer uropod likewise approaches more nearly to the length of the inner 

 ones, though even in full-grown specimens it remains slightly shorter than the latter. 

 This account of the growth changes in T. macrura reduces considerably the points of 

 distinction formerly supposed to exist between it and T. gregaria. The most 

 conspicuous difference is in the proportional length of the last pleon segment, and this 

 distinction would seem to hold throughout life. T. macrura is, besides, a much more 

 slender and graceful form than T. gregaria, with its parts proportionally attenuated. 



Distribution. — T. macrura was recorded from several localities in the Southern 

 Ocean, South Atlantic, and Antarctic Ocean by the ' Challenger.' It has since been 

 noted by Stebbing from the neighbourhood of the Falkland Islands, and by Coutifere 

 from the collections of the French Antarctic Expedition. These records, together with 

 the list of localities for specimens in the present collection, indicate that the species 

 has a wide range in the waters of the southern temperate and Antarctic regions, but 

 its northern limit would seem to be the 40th parallel of south latitude. 



EUPHAUSIAN LaRV^. 



The larvae listed below could not be referred to any species, and are merely noted 

 here for completeness. 



