6 G. O. Sars. 
examined by the above-named gentlemen, and had probably 
not nearly reached to its full size; yet is was so far developed 
as to admit of the assumption that it exhibited all the 
essential characteristics of the species. 
The dimensions of the specimen are as follows: 
Total length, measured from the frontal margin to the 
end of the terminal caudal segment: 13 mm. 
Length of carapace: 8.5 mm. 
Median length of same (to tbe bottom of the posterior 
sinus): 6.8 mm. 
Greatest width of same: 5.5 mm. 
Median length of cephalic part of carapace (to the 
posterior edge of the mandibular segment): 25 mm. 
Width of posterior sinus: 2.9 mm. 
Depth of same: 1.6 mm. 
Length of exposed part of body: 64 mm. 
Length of terminal caudal segment: 0.7 mm. 
Width of same: 1.2 mm. 
Length of caudal filaments: 7.4 mm. 
From the above-given dimensions, it will appear, that 
in the specimen examined by me, the carapace is compara- 
tively larger in proportion to the exposed part of the body, 
the proportion in length between the two being as 4 to 3, 
whereas, according to Messrs, Spencer & Hall, these parts are 
of about equal length. Moreover, the width of the carapace 
in the specimen examined by me, is far from attaining the 
median length, whereas, according to Messrs. Spencer & Hall, 
it exceeds it considerably. On the whole, the form of the 
carapace, when seen from above (fig. 1), looks rather different. 
Messrs. Spencer & Hall describe it as a short oval, and in 
the figure its greatest width occurs considerably behind the 
middle. In the specimen examined by me, it has an oblong 
