CH^ETODERMA. 287 



attenuated, especially the metathorax, which forms about two-thirds 

 the entire length. Smaller individuals with more the proportions 

 of C. nitidulum ; in one about 70 mill, long, the prothorax measures 

 1?, metathorax nearly 1, abdomen 3 mill, in diameter. Mouth- 

 shield (fig. 16) more convex than in C. nitidulum. Dorsal sense- 

 organ (figs. 25, 26) longer, extending to margin of cloaca, having a 

 wide area of short spicules on each side. Gills like those of nitidu- 

 lum, but with not quite so many lateral lamellae, scarcely 20 on each 

 side. Tongue covered with a thick cuticle, which on each side of 

 the tooth and a little backwards is strongly thickened, which is not 

 the case in C. nitidulum. The tooth is almost wholly sunken in the 

 radula sack. Internal structure not differing greatly from C. niti- 

 dulum. 



Kara Sea (Djimnfa Exped.). 



Chcetoderma productum WIREN, Kongl. Svenska Vetenskaps- 

 Akademiens Handlingar, xxv, art. No. 6, p. 8, pi. 1, f. 1-5, 8-16 

 (1892). SIMROTH, Thier-Reich, p. 226, and p. 133, fig. 1. 



C. NITIDULUM Loven. PI. 40, figs. 1-11, 13-15. 



Large individuals 80 mill, long, 3 mill, wide in the middle; aver- 

 age length 30-50 mill. Body cylindrical, of a gray satin-like luster 

 and color, the gills light blood-red or yellowish-red. Dorsal sense- 

 organ (pi. 40, fig. 8), covered with long spicules. 



West coast of Sweden ; Norway ; North Sea at Silverpit ; Spitz- 

 her gen; Kara Sea, east coast of Nova Zemblia; Omenak, northern 

 Greenland, 10 to 250 fathoms; Casco Bay, Maine, 48-64 fms. 

 (Verrill). 



Cha3toderma nitidulum LOVEN, Ofversigt af Kungl. Vet. Akad. 

 Forh., 1844, i, p. 116, pi. 2 (1845) ; Reprinted in Archiv Skandi- 

 navischer Beitrage zur Naturgeschichte, 1845, p. 169, pi. 2, and in 

 Froriep's Neuen Notizen, xxxiv, 1845, figs. 4^-43e. KEFERSTEIN, 

 Beitragen zur anatomischen und systematischen Kenutniss der 

 Sipunculiden, Zeitschr. f. wiss. Zool., xv, 1865, p. 442. HANSEN, 

 Anatomisk Beskrivelse af Chastoderma nitidulum Loven, in Nyt 

 Mag. for Naturvidensk. Christiania, xxii, pp. 354-377, pi. 1-5 

 (1877) ; Neomenia, Proneomenia und Chatoderma, Bergens Mu- 

 seums Aarsberetning for 1888, art. No. vi, p. 6 (1889). GRAFF, 

 Anatomic des Chsetoderma nitidulum Loven, in Zeitschr. fur wiss. 

 Zoologie, xx vi, pp. 166-192, pi. 11-13 ; Neomenia und Chsetoderma, 



