68 THEÉEEL, NORTHERN AND ARCTIC INVERTEBRATES. I. STIPUNCULIDS. 
the number of tentacles and, possibly also, to the colour, the last-named being un- 
certain, as the Siberian forms have been kept in alcohol without any elucidatory in- 
formation on the label. Under such circumstances I think it desirable for the present 
to keep them in this species-group, though pending further investigation I consider 
them as representatives of a "forma orientalis'. Further investigations may throw 
light upon this matter. i i 
The largest specimen attains a length of as much as 210 mm. and has a dia- 
meter of from 14 to 15 mm. "The body has a cylindrical shape, terminates posteri- 
orly in a conical point and tapers gradually towards the tentacle-erown. The pro- 
boscis is, consequently, not very narrow nor does it present any definite transition 
to -the trunk, but appears to pass imperceptibly over into it. One of the best pre- 
served specimens has the following measurements: total length = 150 mm.; greatest 
diameter = 16 mm.; distance between the posterior extremity of the body and the 
anal aperture = 105 mm.; distance between the anus and the oral disk =45 mm.; 
distance between the bases of the ventral retraetors and the posterior extremity of 
the body =56 mm., thus, the retractors are attached to the middle of the trunk; 
distance between the dorsal and ventral retractor bases = 34 mm. The two segmental 
organs, 19 mm. long, open immediately in front of the anus. 
It is evident that the measurements cited do not exactly give the true dimen- 
sions of the living animal, which in reality would be considerably larger. The short- 
ness of the proboscis is, however, striking, for according to DANIELSSEN and KOREN 
in Ph. Hanseni it is somewhat longer than the trunk itself. This peculiarity, together 
with the fact that the number of tentacles is considerably smaller in the Siberian 
gigantice. forms, may possibly justify their being referred to a new species. 
The tentacles have the same aspect as those of Ph. Hanseni and margaritaceum 
but, as already shown, their number is comparatively small, which is seem from the 
annexed table: 
» Forma orientalis» ER TO ine AEG TLocality : 
| 
65 190 mm. > 13 mm. | Pitlekaj, north of Siberia. | 
| 68 | 125 mm. | 15 mm. | Behring Straits. 
| | Så | 125 mm. | 15 mm. | Pitlekaj. 
| 85 | 150 mm. | 16 mm. Behring Straits. | 
The above table exhibits a considerable variation in the number of the tentacles 
— the smallest number is to be found in the largest specimen -— and, besides, it 
shows that "Forma occidentalis'" is in possession of a much greater number of them 
Of course the proboscis is totally devoid of hooks. 
The firm, coriaceous body-wall has, in alcohol, a light dirty brown colour. 
Posteriorly, towards the more or less contracted and wrinkled extremity, the surface 
of the skin is divided into a number of small, irregular, square and slightly convex 
fields, giving to it a reticulate aspect, exactly as is the case in Ph. margaritaceum 
though to a more striking extent. The fields are separated by deeper longitudinal 
