114 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 57 



cavity surrounding the enteric canal, but the presence of distinct 

 segments and parapodia brings Miskoia preciosa under the marine 

 Polychseta. The constriction of the intestinal canal also suggests the 

 Polychaeta. 



MISKOIA, new genus 



The generic and specific description is united under the descrip- 

 tion of the species as there is but one species known. 



Genotype. — Miskoia preciosa, new species. 



Stratigraphic range. — The stratigraphic range is limited to a band 

 of dark siliceous shale about 4 feet in thickness forming a part of 

 the Burgess shale member of the Stephen formation. 



Geographic distribution. — On the slope of the ridge between 

 Wapta Peak and Mount Field, north of Burgess Pass, and about 

 3800 feet above Field on the line of the Canadian Pacific Railway, 

 British Columbia, Canada. 



Generic name derived from Misko, the name of a pass and creek 

 south of Park Mountain and Lake O'Hara, British Columbia, 

 Canada. 



MISKOIA PRECIOSA, new species 

 Plate 18, figs. 1-5 



Body elongate, slender. A specimen 26 cm. in length is i cm. in 

 width at the widest part as it lies flattened in the shale. The body 

 may be roughly divided into three sections : ( i ) The anterior, with 

 the mouth and proboscis as shown in figs, i and 3; (2) the central, 

 which is more or less expanded (fig. 2) ; (3) the slender, terminal 

 section (fig. 5). 



The anterior section merges into the central section so gradually 

 that no definite line of demarcation can be drawn. There is a swell- 

 ing posteriorly and a slight contraction anteriorly that at the end 

 may be a simple opening fringed with fine strong setae (fig. i), or 

 an expanded opening (fig. 3) with the setae radiating from it. 

 When the proboscis is protruded (fig. i) the sides of the anterior 

 section are nearly parallel, and when the proboscis is retracted the 

 sides bulge outward. Usually the proboscis appears to have been 

 cast ofif, in which case the body may contract between the mouth 

 and the expanded central section. The central section may be con- 

 siderably expanded or only a little larger, as shown by fig. 2, which 

 is a portion of the specimen of which fig. i is the anterior and fig. 5 

 the posterior section. 



