POLYCHAETE WORMS, PART 1 97 



abundant in the Grand Banks off Newfoundland. Invades the 

 shallow w^ater near the Ireland coast. Breeds from May until August 

 in Irish waters. Withstands temperatures from 15° to —1° C, 

 optimum temperature being comparatively low. Its salinity range 

 is 31 to 34 %o (above 34 in Irish waters). Seems to be chiefly a 

 coastal form. 



Material examined.- — -Numerous specunens from the Gulf of 

 Maine to north of Bahama Bank, surface to 133 fathoms. Also 

 type of T. smithii Verrill from Eastport, Maine. 



Distribution. — ^Grand Banks off Newfoundland, Gulf of Maine to 

 north of Bahamas, North Sea around Ireland, English Channel to off 

 Portugal, Mediterranean, Sargasso Sea, off South America (mouth of 

 Amazon River), Indian Ocean. Surface to 1,000 fathoms. 



Tomopteris septentrionalis Steenstrup, 1849 



Figure 25c 



Tomopteris septentrionalis Southern, 1911, p. 20.^ — Fauvel, 1923, p. 224, fig. 

 84d.— Huntsman, 1921, p. 90.— Bigelow, 1928, p. 340.— Wesenberg-Lund, 

 1936, p. 4; 1951, p. 32; 1953, p. 34.— St0p-Bowitz, 1948a, p. 49, figs. 3G, 37; 

 1949, p. 12.— Kielhorn, 1952, p. 236.— Uschakov, 1955, p. 110, fig. 13.— 

 Dales, 1955, p. 440; 1957, p. 145, figs. 51, 52.— Berkeley and Berkeley, 1957, 

 p. 575.— Tebble, 1960, p. 176, fig. 8. 



Description. — Length up to 22 mm., width up to 6 mm., segments 

 17-24. Body oval lanceolate, attenuated posteriorly, without a tail 

 region. Both parapodial hyaline and chromophile glands at the apex 

 of the pinnule of the ventral ramus, the hyaline glands (unaffected 

 by hematoxylin) smaU, indistinct, may appear faint reddish brown; 

 chromophile glands (colorless, deeply stained by hematoxylin) ventral 

 to the hyaline glands. Gonads develop in dorsal rami only (fig. 25c). 



Biology. — Characteristically an oceanic species found in deep-sea 

 areas where it may dominate the pelagic community of the surface. 

 Found at all depths to 900 fathoms but especially abundant in surface 

 waters. A eurythermic species, inhabiting the cold and temperate 

 waters of both hemispheres. Breeding season probably prolonged 

 over a long interval, reaching its maximum in the months of autumn 

 in West Greenland waters (Wesenberg-Lund, 1936). In the Lab- 

 rador Sea, specimens caught generally in night surface tows, both 

 adults and juveniles occurring together through the year (Kielhorn, 

 1952). Comparatively insignificant in percentage of the total popula- 

 tion, but probably exerts a noticeable effect in the economy of the 

 region. Voracious predator, preying on almost aU of the other 

 animals of digestible size. Dales (1955, 1957) found it to be the most 

 abundant species of Tomopteris in the collections made off the Pacific 

 coast of North America, it being most common north of San Francisco, 



