AET. 18 SYNOPSIS OF CALANOID CRUSTACEA — MARSH 7 



length of the furcal rami is three times the width. They are about 

 half again as long as the third segment. They are ciliate on the 

 inner borders but not covered with coarse hairs or spines as in L. 

 tnacrurus. In the male abdomen (pi. 3, fig. 4) the first three seg- 

 ments are nearly equal in length and tlie fourth and fifth are some- 

 what shorter. 



The first antennae, when reflexed, reach the second abdominal 

 segment. The terminal portion of the right antenna of the male is 

 usually 4-segmented (pi. 1, fig. 8), but sometimes is 5-segmented 

 (pi. 1, fig. 9). The other cephalothoracic appendages of the femala 

 are like L. mao'ui'us. 



The left fifth foot of the male (pi. 3, fig. T) is like that of L. mac- 

 rurus, but the terminal spine of the second segment of the exopod 

 is somewhat longer. The exopod of the right fifth foot of the male 

 is distinctly 3-segmented. The first segment has a spine at the outer 

 distal angle. The second segment is prolonged into the customary 

 hook at the inner distal angle; at the outer distal angle is a short, 

 blunt, curved hook. The third segment is attached by a distinct 

 joint just within the outer hook: It is hook-shaped, curved inward, 

 pointed at the end, about twice the length of the second segment and 

 one-third to one-half its width; it has upon its dorsal surface a 

 curved spine. 



Average length : Females, 2.99 mm ; males, 2.6 mm. 



Reinarks. — L. johatiseni has, so far, been found in only one locality, 

 in a pond on the coast of the Arctic Sea at Collinson Point. 



The distinguishing features of the species are the short furca 

 armed with fine cilia rather than coarse hairs or spines and the 3- 

 segmented exopod of the male right fifth foot. 



Genus OSPHRANTICUM Forbes, 1882 

 Only one species of Ospht^nticuni has been found; therefore the 

 description of the species will serve also for the genus. 



OSPHRANTICUM LABRONECTUM Forbes 



Plates 4, 5 



PotomoiaJiefor fucosus Herkick, 1SS2, p. 224, pi. 2, figs. 12-14, pi. 3, figs. 1-8, 

 13, 14. 



Osphranticum labronectum Forbes, 1882, p. 645. pi. 8, figs. 24, 28, 29, pi. 9, figs. 

 1, 2, 4, 5, 7, 9.--HEERICK, 1884, p. 134, pi. Q', figs. 1-8, 13, 14 ; 1887, p. 12.— 

 DE GuERNE and Richard, 1889, pp. 96, 97, pi. 4, figs. 1, 2.— Herrick and 

 TuKNER, 1895, p. 86, pi. 12, figs. 1-8, 13, 14. pi. 59, figs. 7, 8.— Schacht, 1898, 

 pp. 230-235. — Giesbrecht and Schmbil, 1898, p. 59. — Tollingbr, 1911. 

 pp. 1.51-153, fig. M*.— JuDAY, 1915. p. 241.— Marsh, 1918, p. 774, fig. 1211, 



