206 Canadian Record of Science. 
ANOMALOCARIS CANADENSIS, Sp. NOV. 
— 
Anomalocaris Canadensis ——Outline of a specimen in which nine 
of the abdominal segments are preserved, besides the caudal 
segment. Natural size. 
Body. inclusive of the tail, elongated, slender, decreasing 
slowly in size from the anterior to the posterior end, rather 
strongly curved posteriorly and nearly straight anteriorly, 
the length of the portion preserved varying in different 
specimens from nine to ten centimetres (as measured at 
about the midheight and following the curve of each), and 
the height or depth at the imperfect anterior end, from 
twelve to seventeen millimetres, exclusive of the ventral 
appendages. Body or abdominal segments, which, in all 
the specimens collected, are abnormally flattened laterally, a 
little higher or deeper than long, broader above than below, 
the pair of ventral appendages proceeding from each, nearly 
equal in height or depth to the segment itself. These 
appendages are straight and prolonged downward at almost 
aright angle to the main axis of the body, for although 
there is a slight divergence in each pair, neither are 
directed distinctly backward nor forward. Between each 
pair of segments there is evidence of a wedge-shaped or 
very narrowly triangular lateral area or interval, which is 
broadest or widest below and does not seem to extend quite 
to the dorsal margin. At the posterior end the segmenta- 
tion is very obscurely defined. Caudal spines, which are 
