Marine Copepoda 21 K 



Station 40r. Bernard harbour (outer harbour), Northwest Territories, 

 water depth 10 fathoms, three vertical hauls to 5 fathoms through hole in 

 ice, net number 3, temperature -0-8°C., July 1, 1915. Coscinodiscus and 

 Balanus nauplii were abundant. The copepods present were: Acartia lon- 

 giremis 9 , Oithona similis v , Ectinosoma neglectum and Idywa furcata 9 . 



Station 42?/. Table X. 



StMion 422. See under Pseudocalanus. 



Station 43e. Table VII. A female carried two spermatophores. 



17. Acartia tumida, n. sp. 



Three examples of a third species of Acartia were taken in surface, at 

 stations 13 a, b, c, in company with Calanus tonsus (q. v.) and Acartia longiremis- 

 (q. v.). The position was 54° 30' N., 159° 42' W., July 1, 1913, net number 3. 



Length of female, 2-00 mm.; anterior antennse not exceeding length of 

 forebody, reaching as far as the front part of the genital segment when laid 

 back, having about the same relative length as in A. bifilosa. Rostral filaments 

 are present, widely separated in ventral view; labrum large trilobate with 

 ciUate edges, as figured by Sars for A. longiremis. Lateral borders of last 

 thoracic segment smooth (Fig. 25); urosome smooth, some minute points 

 dorsally near the posterior edge of the genital segment and at posterior edge 

 of the pre-anal segment; anterior antennse without thorns. 



The caudal setse (Fig. 26) were broken, some of their swollen basal parts 

 remaining attached to the short and broad rami. 



Fig. 25. Acartia tumida: end of thorax and the urosome in side view. 

 Fig. 26. Same. Urosome from below. 



In the swimming feet, the terminal seta (st) of the outer ramus is much 

 longer than Re 3, longer in fact than the whole Re, with a strongly serrated 

 outer edge; the arrangement of the setae is the same as in A. clausi. 



Fig. 27. Acartia tumida. Fifth legs of female, shown complete on one 

 side, the basal joints parallel. 



Fifth legs (p 5 9): the basal joints, right and left, are parallel; the terminal 

 joint, representing the Re, has a swollen proximal portion followed by a narrow 



