REPORT ON THE COPEPODA. 53 



1. Undina vulgaris, Dana (PI. XV. figs. 11-15 ; and PL XVIII. fig. 6). 



Undina vulgaris, Dana, Crustacea of U. S. Expl. Exped. (1852), p. 1092, pi. lxxvii. fig. 8, a-d. 

 (?) Undina simplex, idem, ibidem, p. 1094, pi. lxxvii. fig. 9, a-b. 

 Undina inornata, idem, ibidem, p. 1095, pi. lxxvii. fig. 11, a-d. 



Undina longipes, Lubbock, On some Entomostraca collected by Dr. Sutberland, Trans. Entom. 

 Soc, 1856, p. 17, pi. vi. figs. 1-5. 



Length, l-8th of an inch (3'1 mm.). Cephalothorax elongated, cylindrical, rounded 

 in front ; as seen from the side (PI. XVIII. fig. 6) ; the posterior ventral angle is 

 produced usually into two short divergent spines ; seen from behind the angles of the 

 cephalothorax are sub-acute and slightly produced downwards. Rostrum moderately 

 long and furcate. Anterior antennae (PL XV. figs. 11, 12) twenty-five-jointed in the 

 female, twenty- four-jointed in the male, not much longer than the cephalothorax, fringed 

 with short setae, with at distant intervals — notably on the second or third, eighth and 

 seventeenth joints — one considerably longer than the rest; the last joint in the female 

 has three or four short apical setse, the last but one has two, and the penultimate one, 

 long apical seta ; the antenna of the male is angulated at the eighth joint. The second 

 swimming foot in both sexes (fig. 13) has the second joint of the outer branch deeply 

 indented at the base, and produced downwards into a strong spine, the whole external 

 margin having thus a somewhat hatchet-shaped outline ; the terminal spines of the 

 swimming feet are slender, with finely serrated outer margin and bent tip. In the male, 

 the fifth pair of feet (fig. 14) are dissimilar on the two sides, that of the right side 

 excessively long, and when extended reaching beyond the extremity of the tail ; the two 

 basal joints are long and slender, the third much shorter and giving attachment at its 

 apex to a very long attenuated and irregularly flexed claw, and to an irregularly quadrate 

 appendage from which spring a long falcate claw, and a curiously contorted two or 

 three-jointed and flaccid process ; the foot of the left side is two-branched, the inner 

 branch extremely small, three-jointed and simple, the outer somewhat larger, fashioned 

 in the normal manner but devoid of setse, and bearing at the apex of the second joint a 

 minute subulate process. The caudal segments (fig. 15) are about as broad as long, and 

 equal in length to the last abdominal segment; the setse much shorter than the abdomen, 

 except the fourth (counting from the outside), which is much stouter than, and about 

 twice as long as, the rest. 



Sir John Lubbock's measurement is 1-1 0th of an inch, Dana's 1-1 2th of an inch. 



Habitat. — Off Cape Howe and Port Jackson, Australia ; between Sydney and 

 Wellington ; between Api and Cape York ; between Arrou and Banda ; in very many 

 places amongst the Philippine Islands ; off New Guinea and North Australia ; in the 

 Pacific north of the Sandwich Islands ; at Zamboanga, in the Arafura Sea ; off Kandavu, 

 Fiji ; and in all the gatherings that I have examined from the tropical Atlantic, ranging 

 between lat. 10° S., and lat. 25° N. 



