NEMERTEANS OF HAWAIIAN ISLANDS. 
979 
As in Tseniosoma unistriatum, the present species is conspicuously marked, having a whitish or 
very pale-colored body, with a sharply marked dorsal line of reddish brown or black color extending 
the whole length of the body (pi. i, figs. 1, 2). 
After preservation, the body is of moderate proportions, rounded throughout, largest in esophageal 
region a short distance behind mouth; head rounded in front, marked off from body by fairly distinct 
transverse lateral grooves which, when the head is contracted, form an annular constriction imme- 
diately in front of mouth; anterior portion of head, or snout, demarcated from the posterior portions. 
When strongly contracted the head is much swollen and the snout partially withdrawn into the poste- 
rior part of it (pi. i, fig. 2). Mouth and proboscis pore situated as in related species. 
Careful examination of the specimens after clearing in cedar oil and in microscopic sections failed 
to reveal the presence of any ocelli. Their absence is doubtless correlated with the depth at which 
these worms live. Three other, species of the genus, T. australe, T. girardii, and T. nipponense, are 
described by Hubrecht« from the Challenger collections as having been dredged from depths of 300 
fathoms or more. Whether ocelli are 
likewise wanting in these species is 
not mentioned, although nearly all 
the other known species of the genus 
possess them. Mr. R. C. Punnett, 
however, informs me that he has re- 
cently collected an eyeless species in 
Norway. 
Size . — Length of each of two speci- 
mens which were not strongly con- 
tracted, 50 to 60 mm.; width, 1.5 to 2 
mm. Two contracted specimens were 
each 20 to 30 mm. long and 3 mm. 
in diameter in anterior portion of 
esophageal region. 
Color . — After preservation for a 
short time, the whole body is creamy 
white with the exception of a single 
sharply - marked stripe of reddish 
brown extending in the dorsal me- 
dian line throughout the whole 
length of the body. These colors 
probably represent very closely the 
natural coloration in life. 
In the two specimens which are 
fairly well extended (pi. i, fig. 1) the 
dorsal stripe is a narrow line of less than 0.3 mm. in width, but is sharply marked and conspicuous 
throughout because of its very dark color. In the two specimens which are strongly contracted (pi. i, 
fig. 2) the stripe is about 1 mm. in width anteriorly and 0,5 mm. wide farther back. In the extended 
specimens the stripe is only one-eighth as wide as the body, while in the contracted specimens it is from 
one-third to one-fourth the width of the body. 
On the dorsal side of the head the stripe becomes narrower (pi. i, fig. 3) and terminates imme- 
diately above the proboscis pore or very near the exact end of the dorsal surface of the snout. It is 
* also narrower in the posterior half of the body, but extends nearly or quite to the posterior extremity. 
The stripe remains of a reddish brown color after preservation for a few months in alcohol, but at 
the end of a year is hardly to be distinguished. 
Proboscis well developed for the genus; attached to the tissues of the head immediately anterior 
to the ventral brain commissure; composed of the usual muscular, nervous, and epithelial layers. 
Body walls . — The comparative thickness of the various layers which constitute the body walls is 
shown in text cuts 1 and 2. Integument rather high; basement layer thin; cutis in esophageal region 
from two-thirds to three-fourths as thick as integument, its glandular layer being about twice as thick 
as the underlying connective tissue layer (fig. 1). 
Fig. 1 .—Tseniosoma univittatum sp. nov. Portion of transverse section of 
body in anterior portion of esophageal region, showing peculiar multi- 
cellular gland (a) situated internal to the body walls and immediately 
outside the esophageal epithelium (eep)- } ( x ) Duct of gland; (ilm) Internal 
longitudinal muscles; (cm) Circular muscles; (olm) Outer longitudinal 
muscles; (cu) Glandular layer of cutis; ( cu ') Fibrous layer of cutis; (bm) 
Basement layer; (i) Integument, x 90. 
Challenger Reports, XIX, p. — , 1887. 
