COPEPODA 211 



but only in small numbers. In spite of small differences I do not doubt that my specimens ought to 

 be referred to Farran's S. ovata. As the maxillae do not possess any amalliform setae, I have referred 

 the species to Scolecithricella, though in several respects it shows great similarity to Scaphocalanus 

 obtusifrons, and perhaps is more related to this species than to Sc. minor. 



68. Lophothrix frontalis Giesbr. 

 (PI. VII figs ;a-d; text-figs 66 a f and 67 a d). 



1895. Lophothrix frontalis n. sp. Giesbrecht, p. 254, pi. II. I 1906. Scolecithrix frontalis Giesbr. Esterly, p. 65 pis 9&I3- 



1898. Scolecithrix frontalis Giesbr. Giesbrecht & Schineil, p. 49. ! 1908. Lophothrix frontalis Giesbr. Farran, p. 58. 



1903. J.C.Thompson, p. 21. j 1908. Scolecithrix frontalis Giesbr. v. Bremen, pp. 79 80, fig. 93. 



1904. Lophothrix frontalis Giesbr. Wolfenden, p. 120 pi. IX 



figs 4142- 



1905. G. O. Sars, p. 6. 



1909. Lophothrix frontalis Giesbr. A. Scott, p. 99, pi. XXVI figs 



ii 20, pi. XXIX figs i 10. 

 1911. Wolfenden, p. 268. 



1906. Pearson, p. 19. 



Description. f$. Size of female from Thor St. 72 was 6-45 mm.; anterior division 5-18 mm.; 

 urosome 1-27 mm. Giesbrecht's specimen measured 6'6 mm., Scott's 7-4, and Wolfenden's 5-5 6-0 mm. 



The genital somite is slightly produced below and has an elongate receptaculum seminis, which 

 is directed upwards and forwards (text-fig. 66 a). Along the hinder margin of somites 24 a well devel- 

 oped serration is found; the third and the fourth somites possess dorsally and anteriorly transverse 

 groups of short spines. 



The antennulae, which extend beyond the end of the third abdominal somite, consist of 24 seg- 

 ments, as segments 24 and 25 are fairly well separated. "^)sthetasken" are, in contrast to Scott's figure, 

 beyond segments 8^9 only found in segments 12, 14, 19 and 25. The segment 10 possesses a well 

 developed seta, and a proximal seta is beyond segment 8^9 only found in segments 12, 14 and 18. 

 The Sp of segment 24 extends distinctly beyond the end of segment 25. Segments 8029 are only a 

 little shorter than segment 18, which is a little longer than segment 17 as well as 19, which is 1-2 as 

 long as segment 20. The antennae are like Giesbrecht's figure, with the exopodite a little longer 

 than the endopodite, which has 8 setae in the Li and 6 in the Le. The third basipodite of the man- 

 dibulae has three long convex setae; the first inner segment has 2 setae, and the second has 9. The 

 maxillulae are like those of 5. Magnus, with 7 + 2 setae in L,e, 14 setae in Li I, 2 in Li II, 5 in Li III 

 and 4 or 5 in basipod. III. The Ri I has 3 setae, the Ri II 02 III 5 setae, and the Re has 9 setae. 

 The shape of the maxillae is like that of fig. 143; amalliform as well as vermiform setae are found. 

 The maxillipeds are like Giesbrecht's description. The second, third and fourth pairs of legs do not 

 show the marked difference in the second basipodite when observed in lateral view in situ; in the 

 second and third feet an outer-edge lamina is found, but neither spines nor distal tooth. The first outer 

 segment of the first foot has no outer seta. The second foot has a well developed long outer spine in 

 the first inner segment, as figured by Giesbrecht; the anterior surface is smooth, but the posterior 

 surface has a number of short spines, as seen in fig. 7 a PL VII. The fourth pair of legs has the inner 

 margin of the second basipodite smooth; the third basipodite has, like the third pair, a small inner 

 tooth on the anterior surface near the end ; a few teeth were found only on the posterior surface of the 



two inner segments. TheyS/% pair of legs is scarcely different from Giesbrecht's description. 



27* 



