156 A REPORT ON THE SIPUNCULOIDEA, COLLECTED BY DR WILLEY 



13. Physcosoma pacificum Keferstein. (III.) 



Numerous specimens from Uvea, Loyalty Islands, and a single specimen — rather 

 a small one — from Blanche Bay, New Britain. 



The introvert was in every case retracted, and in this condition the length of 

 the body reached a maximum of some 11 cm. Many specimens were however shorter. 

 The species is widely distributed throughout the Indian and South Pacific Oceans. 



14-. Physcosoma scolops Sel. and de Man. (VIII.) 



A few specimens from Sandal Bay, Lifu, Loyalty Islands. 



The specimens were all small and apparently young forms. In the one I opened 

 there was a curious abnormality in the nephridia. One was small and almost without 

 pigment, but the other was large, dark brown and forked, the two branches being 

 equal in size. 



This species has been recorded from Koseir in the Red Sea, Singapore, the 

 Philippines, and Amboyna in the Moluccas. 



Fischer regards this species as a variety of Physcosoma granalatum, and if this 

 is so, the species occurs on the East and West coasts of Africa, and in the Medi- 

 terranean and Adriatic Seas. 



15. Physcosoma spengeli Sluiter. (XIII.) 



Several specimens from Lifu, Loyalty Islands. 



Sluiter gives the relative lengths of the diameters of the body, but does not 

 mention the absolute length. Dr Willey's specimens varied much in size, the smaller 

 being some 7 — 8 mm. long, the larger when fully stretched out, but not with the 

 introvert everted, some 2"5 cms. All the specimens were somewhat bent, i.e., new 

 moon shaped. 



VI. Genus. SIPUNCULUS, Linnaeus. 



16. Sipunculus australis Keferstein. (IV.) 



Eight specimens from Lifu, Loyalty Islands. 



Dr Willey's specimens measured from 5 cm. to 18 cm. or so, and were all of a 

 dark almost purplish colour. 



S. australis is described in the books as the only species of Sipunculus which 

 bears hooks on the introvert. A closer examination of the cuticular structures of the 

 introvert shows that they differ materially from the hooks of Physcosoma. Like them 

 however they are cuticular, arranged in circles and bear a definite relation to the 

 glandular bodies of the introvert. This relation is shown in the Figure 4. A transverse 

 section (Fig. 5) shows that the relation of these cuticular structures to the underlying 

 epidermis is similar to that of the Physcosoma hooks, but if isolated by boiling in 

 caustic potash it is immediately apparent that their shape is different. Dr Johnson 

 gives as the primary definition of a hook "Anything bent so as to catch hold " : if 



