200 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 57 



Family AGLASPID^ Clarke 

 MOLARIA, new genus 



The description of Molaria is outlined in that of the type species. 



Genotype. — Molaria spinifera, new species. 



Stratigraphic range. — The stratigraphic range is Hmited to a thin 

 layer of dark siliceous shale about 2 inches in thickness forming the 

 base of the phyllopod bed of the Burgess shale member of the Ste- 

 phen 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. 



The generic name is derived from Molar, the name of one of the 

 mountain peaks east of the " Valley of the Ten Peaks," south of 

 Laggan, Alberta, Canada. 



The family reference is tentative. 



MOLARIA SPINIFERA, new species 



Plate 29, figs. i-S 



The dorsal test, when flattened on the shale and viewed from 

 above, is elongate-oval in outline with a long, slender telson ; it is 

 obscurely trilobed longitudinally. Surface slightly roughened by 

 minute shallow punctse. Cephalic shield semicircular in outline, 

 moderately convex. It is divided into a central area with a conical 

 outline corresponding to the glabella of the trilobite and three trans- 

 verse lobes are indicated by short furrows on each side. Postero- 

 lateral angles without genal spines. 



The examination of over 20 specimens has failed to reveal any 

 traces of an eye on the cephalic shield. This might escape observa- 

 tion, but from the close relation of this species to the species in the 

 genus Habelia it is probable that the eyes were pedunculated and 

 beneath the rim of the cephalic shield. 



Thorax with eight transverse segments divided into a median and 

 two lateral lobes. The form and arrangement of the segments is 

 clearly shown by figure 2. Abdomen with one long segment and a 

 slender, spine-like telson. 



Appendages. — The appendages of the head are not satisfactorily 

 preserved. In one (fig. 5) a pair of short, jointed antennules (a') 

 may be traced by their impression on the test to where they extend 

 beyond the rim of the cephalic shield. On the left a larger and 

 longer appendage may possibly represent an antenna. Several speci- 

 mens show slender jointed appendages projecting from beneath the 



