54 THÉEL, NORTHERN AND ARCTIC INVERTEBRATES. I. SIPUNCULIDS. 
Sipunculus norvegicus DANIELSSEN 1868, KOREN and DANIELSSEN 1875 & 1877. 
Habitat: 
West Coast of Norway: Hardangerfjord at a depht of 250 fathoms and in 
Bergenfjord at a depth of 150 fathoms, on a soft, rather sandy, clay-bottom (Mus. B-.). 
General distribution: 
Atlantic Ocean: Azores I:s, 1385 m. (SLUITER'!). 
Thanks to Dr APPELLIÖF I also got an opportunity of examining a small type 
of this form of the two Norwegian investigators. It attains a length of only 15 mm., 
has the proboscis drawn within the body, and its general state of preservation leaves 
a good deal to be desired. The exterior appearance even does not agree with the 
description given by KOREN and DANIELSSEN, because it is totally devoid of the 
annular fold or ridge, which is stated to be so characteristic and to form a line of 
demarcation between the "glans and the trunk itself. Nevertheless the boundary 
between the two parts of the body is discernible in the longitudinal muscular bund- 
les which are visible through the skin and disappear just at the beginning of the 
<olans"". 
Now the question is, whether the two forms of Sipunculus really are distinct 
species, or only represent different developmental stages. I am myself very much 
inclined to consider them as representatives of the same species. In both of them 
the general shape of the body is quite the same, but Sipunculus priapuloides is much 
larger, according to KOREN and DANIELSSEN 115 mm. long and 55 mm. in ”circum- 
ference"', while Sipunculus norvegicus 1s stated to only attain a length of 40 to 60 
mm. Seeing that the specimen at my disposal has a length of only 15 mm., it is 
evident that we have to do with different stages of maturity. 
Supposing that the statements of KOREN and DANIELSSEN were correct, there 
ought nevertheless to exist some differences in the outer appearance between the 
two Sipunculus-forms. Thus, with regard to the posterior portion of the body of the 
smaller form, the authors named write: "Towards the posterior part, the skin forms 
a prominent fold, which goes like a ridge round the body, whereby there is formed 
an evident glans, 9 mm. long. The posterior end of this is rounded, and has in the 
middle an extremely fine hollow, wherein however there is no opening". As to the 
larger form, Sipunculus priapuloides, they say: "The latter [glans], which is 30 mm. 
long, smooth and perfectly like the glans of the virile member, forms above a rather 
large, freely standing prominence; properly a fold in the skin surrounding the whole 
back and the side part, until near the ventral surface, where it is elongated on each 
side, converging backward with about 4 mm. on the round end, whereby there is 
produced, on this part of the glans, a furrow which is widest in front. The superior 
margin of the prominence has a ecrenulated appearance, while the ventral margins 
1) Géphyriens (Sipunculides et Echiurides) provenant des campagnes de V'Hirondelleet de la Princesse- 
Alice (1886—1897). Monaco 1900. 
