108 
THEEL, NORTHERN AND ARCTIC INVERTEBRATES. I. SIPUNCULIDS. 
Plate IV. 
Figs. 34—37. Phascolosoma margaritaceum (M. SARS). 
A piece of the skin slightly in front of the posterior end of the body. 55. KOREN'S 
and DANIELSSEN'S type from Finmarken. 
Sample of skin close to the posterior extremity of the body. 365. Tromsö. 
Sample of skin, slightly more in front of the posterior end of the body. 35. Young spe- 
cimen from Bel Sound on Spitzbergen. 
Sample of skin from the hindmost part of the body. >;f. Small specimen from Clavering 
Island off the East Coast of Greenland. 
Figs. 38—43. Phascolosoma Hanseni (DANIELSSEN and KOREN). Arctic Sea. 
(Figs. 38—40 are drawn with the light thrown upon the object, while all the remaining 
samples of skin are drawn under the microscope with the light transmitted through the 
object.) 
Sample of skin, 55 mm. from the posterior extremity of the body. 2. The winter 
harbour of the Vega off the North coast of Asia. (Forma orientalis.) 
Sample of skin, 15 mm. from the posterior end of the same animal. ?p. 
Sample of skin from the hindmost end of the same animal. >. 
Sample of skin from the posterior end of a highly contracted and wrinkled typical spe- 
cimen from Ice Fjord in Spitzbergen. 36. (Forma occidentalis.) 
Sample of skin of a very macerated specimen taken from slightly in front of the posterior 
end. 36. North of the winter harbour of Vega. (Forma orientalis.) 
Sample of skin from the posterior extremity of the same animal. 5, 
