COPEPODA. 11 



segment laterally produced somewhat and ending in short points. Anterior antennae 

 about as long as the furca, or about one joint longer. 



Genital segment as long as the next two. Furca three times as long as broad, and 

 longer than the anal segment. 



Second feet, Re 3 divided by the marginal spine into two about equal parts. 



Third feet, Ri 3 with eight bristles (four outer, two apical, two inner), Re 3 

 divided into two parts, of which proximal : distal = 17 : 13. 



Fourth feet, Re 3 divided by the marginal spine, proximal : distal = 20 : 11. 



Ri 3 with seven Si (two outer, two apical, three inner), terminal saw of Re 3 only 

 three-quarters as long as Re 3. 



Fifth feet B 1 toothed, with fourteen teeth on the rather convex margin, and at 

 the distal end a slight break in the continuity, with three rather larger teeth somewhat 

 hidden, in front view, by the upper teeth of the marginal surface. Ri 3 with five bristles 

 (two inner, thin and short, two apical, and three outer). In the second pair the Ri 

 reaches about the end of the Re 2, in the third pair to the first inner marginal bristle 

 of the exopodite, and in the fourth pair as far as the second inner marginal bristle, in 

 the fifth pair beyond the origin of the first inner marginal bristle. The endopodites 

 are therefore proportionately larger than in C. tonsus, and the third segment of the 

 exopodite is not four times as long as broad. 



While this species agrees with C. propinquus in many particulars, the proportions 

 of the third and fourth feet differ, also the toothing and convex margins of the basals 

 of the fifth feet, and the size. Many of the examples were quite adult females with 

 spermatophore attached, so there can be no question of their being merely undeveloped 

 examples of C. propinquus, and, as before mentioned, this species has a considerable area 

 of distribution in the southern oceans. 



4. Calanus tonsus. 

 (Plate I., figs. 7, 8.) 



Calanus tonsus, Brady, Eep. XIX., ' Chall.' Report, p. 34. 

 Scott, Tr. Linn. Soc. VI. (1893), p. 25. 

 „ „ Giesbrecht, Fauna u. Flora Neap. XIX., p. 92. 



Dahl, Verb. Deutsches Zool. Gesells. IV. (1894), p. 77. 



Brady's original description of this species is very incomplete, and he merely states 

 that it is " like C. finmarchicus and propinquus, except that the anterior antennae are 

 almost devoid of setae, except on the three apical joints ; the posterior antennae are like 

 those in C. propinquus, the fifth pair without basal teeth, and the first abdominal 

 segment large and tumid. The anterior antennae are as long as the body .... 

 9 Size 3 ' 6 mm." He gives only two figures — viz., of the anterior antennae and the 

 abdomen. 



Giesbrecht includes it under the " Unbestimmbare species," remarking that the 



