KUNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 39. N:o |. 81 
DANIELSSEN and KOREN state that the species in question is provided with a 
single segmental organ. I am not able to verify this statement, but I do not believe 
it to be correct. The whole organisation goes to show that there must be two such 
organs. The same authors also state: "There is only one retractor, springing from 
the middle of the body with a broadish root, which in some of the specimens had a 
slight incision:'"" My own investigations have led me to the conviction that here also 
there are two retractors present, embracing the nervous cord with their roots. But, 
of course, they are webbed together anteriorly. 
For the remaining organisation I am compelled to refer to the statements of 
DANIELSSEN and KOREN. 
Phascolosoma Sabellari2 n. sp. 
PI. V. Figs. 44—50, PI. XII. Figs. 175—176, PI. XIV. Figs. 197-201. 
Total length of the largest specimen 15 mm. Proboscis more than a third of 
the total length. Trunk cylindrical, sligthly tapering anteriorly and behind. Tentacles 
absent and replaced by some irregular, rounded prominences of the oral disk. Skin 
hyaline, shining, smooth and devoid of papille. Hooks absent. Two ventral retractors 
embracing the nervous cord with their roots and attached at about the middle of 
the trunk or slightly behind it. Two free segmental organs. Intestinal spiral, com- 
posed of about 13 double turns and not attached posteriorly. Body-cavity always 
filled with eggs in all developmental stages. 
Habitat: 
West Coast of Sweden: Elleskär, a diminutive island situated west of the fjord 
of Gullmarn between the islands of Bonden and Gåsö. Close by this rock there is 
to be found, at the trifling depth of 8 to 10 fathoms, a hard sandy bottom covered 
with shells of extinet Cyprina islandica; their surface is enveloped by a thick layer of 
sandy tubes formed by Sabellaria spinulosa of R. LEUCKART. Hidden between these 
tubes there exists a rich fauna, representing a very characteristic formation of ani- 
mals comprising Polycheta, Gephyrea, Turbellaria, Nemerteans, Nematoidea, Bryozoa, 
Mollusea, Ostracoda, Isopoda, ete. Among the Gephyrea there is to be found an 
abundance of the minute forms which I have called Phascolosoma Sabellarie and 
improvisum. 
Among the large numbers of individuals which I have examined, no single one 
has been found to exceed a length of 15 mm. During the months June to 
Mars the body-cavity is always filled with large ova. The elongate trunk (Fig. 44) 
does not attain two thirds of the total length of the animal, but is considerably more 
than half of it. The glandular bodies of the skin (Figs. 45—49) do not, as a rule, 
protrude beyond the level of the body-wall, and when they do so, it is to a very 
inconsiderable extent (Fig. 49). As a rule the hooks are quite absent, but in some 
very rare cases (1 ”/,), there are to be observed a very few small ones scattered about 
