22 THE VOYAGE OF H.M.S. CHALLENGER. 



consist of five or six longitudinal muscles, the narrower dorsal of one or two, originating 

 a short distance in front of the former. The contractile tube is simple. On the intestinal 

 spiral there are only from twelve to fourteen double coils. The posterior fourth part of 

 both segmental organs is free. 



Habitat. — This species has a somewhat wide range of distribution. Specimens have 

 been obtained from the Philippines, from Singapore, and from the Eed Sea ; and Peters 

 found a varietj" off Mozambique. 



The single small specimen of the Challenger Expedition was labelled Station 208, 

 January 7, 1875; lat. 11° 37' N., long. 123° 31' E. ; depth, 18 fathoms; blue mud; 

 trawled. 



In the manuscript left b)^ the late von Willemoes-Suhm I find some sketches and 

 notes of a Sipunculid, which he considered as representative of a new genus. It is, 

 however, a true Phymosoma, and seems indeed to be closely related to Phymosoma 

 varians. But since the single specimen is only imperfectly preserved, so that a 

 satisfactory diagnosis is now impossible, and since, further, the form exhibits no 

 characters of special interest, I content myself with this reference. 



Genus 10. Sipunculus, Linne. 



The longitudinal musculature is divided into seventeen to forty-one bands. The 

 proboscis has four retractors. The body is destitute of papillae. The tentacles always 

 surround the mouth, and either form a lobed membrane or are finger-shaped. There are 

 no hooks, except in Siptonculus australis. Most of the species are large. They are 

 found in all seas. 



23. Sipunculus nudus, Linne. 



This species, named by Linne,' is thoroughly described in Die Sipunculiden {loc. cit.), 

 pp. 92-95. 



Habitat. — It has been found in the Mediterranean, on the west coast of France, in the 

 North Sea, off the West Indies, Florida, and the Philippines. The two specimens 

 preserved came from the Spanish coast and from the North Sea, and are labelled as 

 follows : — 



(a) H.M.S. " Porcupine," No. 30, August 2, 1870 ; lat. 36° 15' N., long. 6° 52' W. ; 



depth, 386 fathoms. 

 {b) H.M.S. "Porcupine," No. 22, 1869 ; lat. 56° 8' N., long. 13° 34' W. ; depth, 

 1263 fathoms. 



'■ Sy.stema Naturne, Editio duodeciraa I. HolmicT, 176G, p. 1078. 



