62 THEEL, NORTHERN AND ARCTIC INVERTEBRATES. I. SIPUNCULIDS. 
ago, it may be easily understood, why I was not able to identify correctly the forms 
I had before me. 
A renewed examination has proved that SELENKA is right in his supposition 
that my form "”validum"" 1s provided with only two segmental organs. KOREN and 
DANIELSSEN deny the presence of hooks behind the tentacles of their Phascolosoma - 
papillosum. I owe Dr APPELLÖF of Bergen many thanks for having given me an 
opportunity of examining the type-specimen in the museum there, and I am thus 
able to state that the form examined by the two Norwegian investigators really is 
in possession of well-developed hooks (fig. 14). 
The 'tentacles (Fig. 186) vary considerably in number. In the specimen figured 
by me I counted 70; in somewhat smaller ones I found them there were sometimes 
60, sometimes fewer. The hooks (Figs. 2 and 4) are sometimes rather coarse. I 
refer further to the plates. 
Phascolosoma elongatum KEFERSTEIN 1862 and 1865. SELENKA 1883. 
Pl. I. figs. 9—13 and PI. XITI. fig. 188. 
Habitat: 
West Coast of Sweden: Väderöarne, clay, 60 fms. (Gunh. Exp. ""/; 1877), 1 sp.: 
Gullmarn at different depths and on different bottoms; a few specimens only. During 
the last few summers two or three samples have been procured by dredging in the 
vicinity of the Marine Biological Station Kristineberg — Gåsö, Löken, Flatholmen 
and Fittebojar, 45 larger and smaller specimens (Mus. G.). 
General Distribution. 
Coast of France (KEFERSTEIN, GRUBE, SELENKA etc). Mediterranean sea (CLA- 
PAREDE). To my knowledge Ph. elongatum has not yet been met with, either off 
the Danish or off the Norwegian coasts, though it very likely lives there. 
With a general reference to the descriptions of my predecessors, I confine myself 
to the following data. The largest specimen discovered off the Swedish coasts, has 
a total length of 80 mm. In a smaller sample, somewhat more than 50 mm. in 
length, the number of tentacles amounts to 22 (Figs. 11 and 188). The ”ciliated pad” 
is divided by two longitudinal furrows into three portions (Fig. 188). The hooks 
(Figs. 10 and 11) decrease posteriorly, where they also present a more irregular arran- 
gement. In one sample I found them disposed in about 16 distinct rings. TI have 
réason to believe that the number of hook-rings, at first insignificant, gradually in- 
creases during the growth of the animal, and finally becomes reduced. Thus, in some 
of the oldest specimens I counted only from 5 to 7 complete rings. The elongate, 
cylindrical body has the posterior extremity more evenly rounded than is the case in 
Phascolosoma vulgare. At that extremity the glands of the skin are more or less 
rounded and very crowded together. 
