l8o SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 57 



nal section points to the disappearance of appendages such as occur 

 in the Apodidas and the diminution in size of the abdominal seg- 

 ments and probably to the ultimate disappearance of most of them. 



Formation and locality. — Middle Cambrian: (35k) Burgess shale 

 member of the Stephen formation, on the west slope of the ridge 

 between Mount Field and Wapta Peak, one mile (1.6 km.) northeast 

 of Burgess Pass, above Field, British Columbia. 



Family (undetermined) 



Genus ANOMALOCARIS Whiteaves 



ANOMALOCARIS GIGANTEA, new species 



Plate 34, fig. 3 



Practically all that is known of this species is illustrated by figure 

 3 of plate 34 (natural size), which gives a side view of the abdomen 

 o£ the species. Nothing is known of the carapace or of the details of 

 the appendages more than that for each segment there are two strong 

 pointed appendages that appear to be composed of two joints ; the 

 long, narrow, sharp distal joint, and a short, broad proximal joint. 



One specimen found in association with the other fragments indi- 

 cates, if it belongs to the same species, that the abdomen terminated in 

 a short, strong, slightly curved telson. 



This species differs from Anomalocaris canadensis Whiteaves ' 

 in its greater size and more compact abdominal segments. 



It is hoped that more perfect material will be found at the Burgess 

 Pass locality that will enable us more clearly to determine this species, 

 also to discover the nature of its carapace and that of the other de- 

 scribed species of Anomalocaris which occur on the slope of Mount 

 Stephen at nearly the same horizon about six miles away. 



Formation and locality. — Middle Cambrian : (35k) Burgess shale 

 member of the Stephen formation (phyllopod bed), on the west 

 slope of the ridge between Mount Field and Wapta Peak, one mile 

 (1.6 km.) northeast of Burgess Pass, above Field. British Columbia. 



WAPTIDJE, new family 



A transition form between the Branchiopoda and Malacostraca 

 with a small carapace covering more or less of the cephalic and 

 thoracic region. Abdominal region with 6 segments the last of which 

 bears a pair of fin-like rami or a slender telson. 



^ Canadian Alpine Journal, Vol. i, No. 2, 1908, pi. 2, fig. 3a. 



