92 THÉEL, NORTHERN AND ARCTIC INVERTEBRATES. I. SIPUNCULIDS. 
on the same label is also noted "the reef of Jutland'', in the neighbourhood of the 
Shetland Islands. In 1875 I fixed the length of this species as 30 mm. Now, after 
examining the new form, I am able to ascertain that the body itself, including the 
shield, measures about 25 mm. The proboscis being drawn within itself, its true length 
cannot be stated, nor the number of the tentacles. With regard to the hooks and 
the glandular bodies of the skin I refer to my former paper and to the figures in 
this report. The blackish brown shields are composed of closely erowded, small, ir- 
regularly rounded or polygonal, chitinous plates. The anterior shield, situated dor- 
sally between the anus and the true narrow proboscis, presents on its outer surface 
a series of somewhat light coloured furrows, 2 or 3 running transversely in front and 
several longitudinal ones to the rear, longer alternating with shorter. The posterior. 
shield shows about 18 furrows, running from the periphery towards the central top; 
here also long furrows alternate with short. In the specimen from Bohuslän the 
arrangement of the furrows is more indistinet, because they anastomose in various 
ways with each other. The concave interior space of the anterior shield is traversed 
by 11 bright, powerful, tendinous muscular bundles or bands which converge anteri- 
orly. The two free segmental organs open into the body-cavity by means of a di- 
stinet pore. The two ventral retractors are attached to the posterior shield near to 
its centrum, where they embrace the nervous cord. In the specimen from Bergen 
or Shetland Islands, near to its middle, the longitudinal muscular layer of the body- 
wall shows traces of being composed of separate anastomosing bundles. The intesti- 
nal spiral has about 28 or 30 twists and is in possession of a powerful spindle- 
shaped muscle, attached anteriorly neer to the posterior margin of the anal shield 
and posteriorly to the caudal shield, though slightly eccentric. 
The specimen brought home from Bergen or from the "Treef of Jutland'”' is 
slightly darker, owing to the dark chitinous plates of the skin which are crowded 
together especially at the anal portion of the body. 
In order to facilitate the comparison of this species with the following one, it 
may be as well to summarize here the characteristics of it: 
Length of the trunk about 25 mm.; length of the proboscis unknown. Tentacles 
unknown. 
Hooks small, curved, only present on the anterior portion of the proboscis and there 
arranged in at least 80 annulets. 
Anterior and posterior shields show a series of distinct furrows. Interior space of 
the anterior shield strengthened by 11 bright, tendinous muscular bands. 
Two ventral retractors anteriorly united and embracing with their bases the nervous 
cord, and attached to the posterior shield near to its centre. 
Two free segmental organs. 
Intestinal spiral with from 28 to 30 twists, and provided with a powerful spindle- 
shaped muscle, fixed posteriorly to the caudal shield, 
