78 THE ROYAL SOCIETY OF CANADA 

Fig. 1. Urosome of Centropages hamatus ® from the dorsal surface. 
Fig. 2. Fifth thoracic limb of Centropages hamatus 9 
Fig. 3. Fifth thoracic limbs of Centropages hamatus © 
Corycaeus affinis, n. sp. 
This is a small form, the male measuring about 0-83 mm. in 
length, and it has the anterior division of the body clearly divided 
into four segments (Ce and Thy, Ths, Th; and Thy, while the abdomen 
consists of two segments, genital and anal, exclusive of the furca. 
The ventral keel is continued posteriorly into a beak-like prolongation 
overlapping the first thoracic segment (fig. 4), but the prolongation 
seems to be much less prominent than in the rostratus group, from 
which the present form also differs in the greater number of abdominal 
segments. Of these, the furca and anal segment together fall a 
little short of the length of the genital segment in both sexes, the pro- 
portions of the three parts, measured in five examples, being approxi- 
G 
t 
Fig 4 
Fig. 4. Side view of Corycaeus affinis. t—tongue-like prolongation of ventral 
keel; G—genital segment. 
