Echinoderes arlis n. sp. — Higgins 
519 
0.50-0.59 X the trunk length; lateral accessory 
spines measured 67-80p in length, 0.28- 
0.32 X the lateral terminal spine length; mid- 
dorsal spines of segments 6, 8, and 10 measured 
73-7 6p, 92-110p and 115-126(1 in length; 
lateral spines were more nearly equal in length, 
measuring 34-45u. 
The range in trunk length for all males 
examined was 382-420(i; the maximum sternal 
width occurred at segment 10 and measured 
73-80(1, giving a trunk length-msw ratio of 
5.2:1 in all males. The sternal width at segment 
12 measured 65-71(1, giving a trunk length- 
sw-12 ratio of 5.9:1 in all males. Lateral ter- 
minal spines measured 230-238(1 in length, 
0.55-0.62 X the trunk length; the lateral acces- 
sory spines were measured only in the allotype ; 
middorsal spines of segments 6, 8, and 10 
measured 79-89[a, 98-105(1 and 105-115(1 in 
length; lateral spines were more nearly equal in 
length, measuring 33-44(1. 
type locality: 74.5° N, 163.9° W, from a 
depth of 747 m. 
material examined: Six specimens; four 
females and two males. Holotypic female 
(author’s number K 57.1) and one other female 
from type locality, station 360, Arctic Research 
Laboratory Ice Station 1 (arlis-1, from which 
the species name is derived), off Point Barrow, 
Alaska, collected by John Tibbs, 16-17 January 
1961. Allotypic male (author’s number K 58.4) 
one other male and two females from station 
446 (74.8° N, 165.6° W), arlis-1, collected 
by John Tibbs, 9-10 February 1961, from a 
depth of 419 m, 
disposition of types: Holotypic female 
(usnm 32924), and allotypic male (usnm 
32923) have been deposited in the marine 
invertebrate collection of the U. S. National 
Museum. The remaining paratypes are in the 
author’s personal collection. 
remarks: Echinoderes arlis n. sp. is within 
the size limits of several species including E. 
pilosus Lang, 1949, E. hengalensis (Timm, 
1958), E. pennaki Higgins, I960, and E. 
hrevispinosus Higgins, 1966, but differs from 
these by having elongate middorsal spines on 
segments 6, 8, and 10. Only one species, 
E. riedli Higgins, 1965, has the same middorsal 
spine arrangement and this is a very small 
2 
Figs. 1 and 2. Echinoderes arlis n. sp., holotypic 
female, neck and trunk segments (head retracted). 
Fig. 1, dorsal aspect; Fig. 2, ventral aspect. 
species, 228p in length, recently described from 
the Red Sea. 
The lateral spination of E. arlis n. sp. is 
shared by E. setigera Greeff, 1869, E. pilosus 
and E. levanderi Karling, 1954, but other than 
for E. setigera , whose middorsal spines are on 
segments 6, 7, and 9, the remainder have a full 
complement of middorsal spines on segments 
6 through 10. 
In addtion, E. arlis n. sp. dffiers from all 
other members of this genus by the shape of the 
terminal border of segment 13. 
ACKNOWLEDGMENTS 
I am grateful to Dr. John L. Mohr, Dr. 
Stephen R. Geiger, and Dr. John Tibbs, Uni- 
versity of Southern California, for their gen- 
erosity in providing the specimens. The speci- 
mens were collected with support by contract 
