184 Transactions. — Zoology. 



Unfortunately, in preparing my list of worms for the 

 Index F.N.Z. I had not had time to fully examine the 

 character of the tentacular crown, or to compare my speci- 

 mens with what appears, from Captain Hutton's information, 

 to be the type of his Sipuncuhis httulentus, so that this sipun- 

 culid appears as Phascolosojna huttoni. 



EXPLANATION OF PLATE VII. 



Figs. 1-10 represent Physcosoma anmdatum. 

 Pigs. 11-14 represent Dcndrostoma aneum. 



Fig. 1. Physcosoma (natural size) with the introvert retracted. This is 

 the usual condition in which the animal dies — the position of 

 rest. 



Fig. 2. A small individual with the introvert fully extended (natural 

 size). The distal extremity of the introvert, seen from in 

 front. 



Fig. 3. Showing the tentacular crescent overhanging the mouth (en- 

 larged), with the brain above. 



Fig. 4. The distal extremity of introvert from the side (enlarged), show- 

 ing the rings of booklets. 



Fig. 5. A booklet (much enlarged). 



Figs. 6, 7, 8, 9 illustrate the different forms (natural size) of body 

 assumed on death, and may to some extent be regarded as 

 various phases of movement during life. In fig. 6 the muscles 

 at the hinder end are strongly contracted and the introvert is 

 nearly fully everted. In fig. 7 the circular muscles in the 

 middle of the body and the introvert are retracted ; while in 

 fig. 8 the longitudinal muscles are in contraction, giving rise 

 to a more or less globular form of body. In fig. 9 the body 

 has a normal shape, of moderate extension, and the introvert 

 is almost completely everted. Figs. 6, 7, 9 represent indivi- 

 duals killed slowly by adding alcohol gradually to sea-water ; 

 while fig. 7 is a specimen killed suddenly by being plunged 

 into alcohol. 



Fig. 10. A specimen with a calcareous cup at the posterior end of body 

 (see next), giving it the appearance of Aspidosiphon. 



Fig. 11. Deiulrostovia cBueum of the natural size. 



Fig. 12. "View of the oral disc and tentacular crown (enlarged). This is 

 so far diagrammatic that on the right side some of the ten- 

 tacles are represented as spread out flat. 



Fig. 1.3. Side view (enlarged) of part of the tentacular crown, showing the 

 2 lobes, each subdivided into lobules, bearing filiform ten- 

 tacles. 



Fig. 14. A horny spine from the introvert (much enlarged). 



