134 PROCEEDINGS OF THE NATIONAL MUSEUM vol.84 



HEPTIUM SCAMILLATUM, new species 



FiGUKE 18, a~c; Pi^vte 4, Figures 5, 6 



Diagnosis. — This is a stouter species than cannelly/m. The tuber- 

 culate anterior half of segment 1, the very abrupt descent of the sur- 

 face to a lower level behind the secondary crests, and the transition to 

 the full number of dorsal crests on segment 18 are other character- 

 istics of this species. 



DescHption. — Body not especially slender, distinctly depressed in 

 both sexes; rather close jointed, the anterior subsegments little ex- 

 posed; length 27 to 34 mm, width 1.8 to 2 mm; number of segments 

 61 to 69 (pi. 4, figs. 5, 6). 



Eye cluster triangular, with 41 to 55 ocelli in 7 or 8 rows; sense 

 organ in fi'ont of the fourth and fifth rows of ocelli. 



First segment with the inner crests reaching nearly halfway to the 

 anterior margin, the two outer crests on each side longer than the 

 others. Surface in front of the crests finely but distinctly and ir- 

 regularly tuberculate. Setae arranged in the usual triarcuate series. 



Dorsal crests thicker and higher than in carinellum.^ and decreas- 

 ing in size more slowly toward the back end of the body. Transi- 

 tion to the full number of dorsal crests occurs on segment 18 

 (fig. 18,^). 



Primary crests with a distinct, finely dentate apex, directly be- 

 neath which on each side is an irregular row of small, almost con- 

 tiguous, circular pits ; the lower sides of the primary crests and the 

 remainder of the subsegment, including the secondary crests, coarsely 

 and very unevenly reticulated. Secondary crests prominent from 

 segment 6 to near the end of the body; entirely lacking or greatly 

 reduced in size on the first five segments ; apex of crests irregular in 

 outline. Behind the secondary crests the surface between the pri- 

 mary crests descends very abruptly to a much lower level, which con- 

 tinues to the back margin, giving the segments a distinctly scalloped 

 appearance behind. 



Poriferous carinae prominent; outer margin strongly and irregu- 

 larly serrate ; the anterior corner broadly rounded and the posterior 

 corner acute and somewhat produced backward (fig. 18, c) ; rim 

 surrounding the pore area decidedly thickened. On the midbody 

 segments the pore is located a little behind the center of the rather 

 broadly elliptic impression which occupies considerably more of the 

 margin than in carinellwii. The two primary crests below the porif- 

 erous carinae higher than those of the dorsum and with 6 to 10 

 conspicuous teeth or serrations along the apex. 



Anterior subsegments not so greatly exposed as in carinellum, and 

 with the posterior channels a little deeper. 



