634 



BULLETIN 54, UNITED STATES NATIONAL MUSEUM. 



a'. Middle and antero-lateral lobes of head truncate. Second article of flagellum 

 of second antenme longest. Terminal segment of abdomen triangulate. Body 

 covered with low tubercles. Fourth and fifth articles of the peduncle of the 

 'antenna; subequal; terminal article of flagellum not minute, but as long as pre- 

 ceding one. Post-lateral angles of the first thoracic segment produced. 



Actoniscus lindahli, new species 



ACTONISCUS ELLIPTICUS Harger. 



Actoniscus ellipticus HARGER, Am. Jour. Sci. (3), XV, 1878, p. 373; Proc. U. S. 

 Nat. Mus., II, 1879, p. 159; Report U. S. Commissioner of Fish and Fish- 

 eries, 1880, Pt. 6, pp. 309-310, pi. i, fig. 3. 



Armadilloniscus ellipticus BUDDE-LUND, Crust. Isop. Terrestria, 1885, p. 239. 



Actoniscus ellipticus UNDERWOOD, Bull. 111. State Lab. Nat. Hist., II, 1886, p. 360. 

 RICHARDSON, American Naturalist, XXXIV, 1900, p. 307; Proc. U. S. Nat. 

 Mus., XXIII, 1901, p. 576; Trans. Conn. Acad. Sci., XI, 1902, p. 305. 



Localities. Savin Rock, near New Haven, Connecticut; Stony 

 Creek, Long Island Sound; Bermudas; Hungry Bay, Bermudas. 



"The body is oval in outline. The 

 head appears triangular, as seen from 

 above, and is angularly produced in a 

 median lobe, but the lateral lobes are also 

 large and divergent and broadly rounded. 

 The eyes are small, oval, black, and 

 prominent. They are situated at the 

 sides of the median triangular part of 

 the head, and at the base of the lateral 

 lobes. The antermulae are minute and 

 rudimentarj 7 . The antennae have the 

 basal segment short; the second enlarged 

 distally, especially on the inner side; the 

 third forming an angle with the second 

 and clavate; the fourth flattened-cylin- 

 drical, longer than the third; fifth long- 

 est, slender, bent at base and forming an 

 angle with the fourth; flagellum shorter 

 than the last peduncular segment, tipped with setae and composed of 

 four segments, of which the second and third are equal and longer 

 than the first, while the last is the shortest and presents indications of 

 another minute rudimentary terminal segment. The maxillipeds have 

 the basal segment nearly twice as long as broad; the terminal segment 

 elongate triangular, ciliated, and somewhat lobed near the tip. 



"The first thoracic segment is excavated in front for the head, 

 admitting it about to the eyes. The next five segments are each a 

 little longer than the first, but the last thoracic segment is the shortest. 

 The first segment is dilated at the sides to about twice its length on 

 the median line. The second and, in an increasing degree, the suc- 

 ceeding segments are produced backward at the sides. The legs are 

 rather small and weak and of nearly equal size throughout. 



FIG. 678. ACTONISCUS ELLIPTICUS 

 (AFTER HARGER). x 10. 



