KUNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 39. N:o l. [al 
are smooth. On the rounded end of the glans there appears a little roundish cavity, 
which, during the contractions, assumes various forms, and acquires sometimes a de- 
ceptive resemblance to an aperture (porus), which however does not exist. By this 
hollow there are produced, as it were, two lips, of which one, corresponding to the 
dorsal side, projects most; moreover, the glans can be strongly contracted; and then 
it assumes the most remarkable forms, always retaining, however, its annular pro- 
minence'"". 
On comparing these two statements of KOREN and DANIELSSEN it becomes 
elear that the proper difference must lie in the fact, that the annular ridge, con- 
fining the glans, is broken in outline on the ventral surface of the larger form and 
bent backward in such a manner that a longitudinal furrow arises. However, I have 
had the opportunity of investigating several large samples of Sipunculus priapuloides, 
some attaining a length of more than 120 mm., but in several instances I have not 
been able to detect any furrow at all. I have reason to believe that this not only 
depends upon the state of preservation but also upon the fact that the furrow in 
fresh specimens may be more or less indistinet. In small and young samples the 
furrow must, of course, be still more inconspicuous, and then the annular ridge, if 
visible at all, may appear as if it was continuous round the body. For the present I 
must be very sceptical as to the value of this character, so much the more so, as 
the small individual of Sipunculus norvegicus examined by me, is devoid of such an 
ffannular prominence"'. 
With regard to the other properties which, according to KOREN and DANIELSSEN, 
mark the two forms as distinet species, I must acknowledge that I am in a puzzle. 
Thus, they say that the proboscis of Sipunculus norvegicus "is thickly covered with 
conical papille, standing in irregular rows which increase in density towards its ex- 
tremity”. As to the proboscis of Sipunculus priapuloides, on the other hand, they 
state that it is "furnished with large prominent conical papillae, which form longitu- 
dinal rows and become smaller towards the oral aperture'". Considering that I have 
not been able to discern an arrangement in rows of the papille of Sipunculus pria- 
puloides, this distinguishing character must be set aside. 
Concerning the tentacles it may be the same thing. With respect to Sipun- 
culus norvegicus the Norwegian authors write that the oral aperture "is surrounded 
by 8 rather thick whitish yellow tentacles, which are nearly lancet-shaped, with ob- 
tuse extremities and below to some extent lobed', and at the end of the diagnosis 
we read: "The tentacular membrane lobed, 8 lobes'". Regarding Sipunculus priapu- 
loides they say: "The tentacular membrane forms 12 lobes, of which 2 are very long, 
one on the dorsal side, and one on the ventral side; the others are shorter; but all 
are more or less cut out at the edge". Thus far it is all very well. The tentacular 
membrane of S. norvegicus, however, is said to have 8 lobes, while that of S. pria- 
puloides is said to be provided with 12. But is it really so? The figures given by 
KOREN and DANIELSSEN show something quite different. They exhibit that in both 
cases only 8 tentacular lobes are present. What can this mean? Both statements 
can hardly be right. Relying on my Fig. 213, I am much inclined to believe that 
