343 
always distinctly developed. In this case the opercular plates will 
be of aid, although according to Hutton (1879) they shall be al¬ 
most identical with those of Elminius modestiis Darwin. Accord¬ 
ing to the specimens from Paterson I nlet obvious differences are 
nevertheless present in the opercular plates: only two or three 
small crests are developed for the depressor of the tergum, and 
the spur is confluent with the scutal margin; in the scutum an 
Fig. 76. Elminius sinuatus from Paterson Inlet. a two specimens seen from above, 
b and c inside view of scutum and tergum, d and e external view of tergum 
and scutum, f mandible, g maxilla. [a x 5,3; b —d X 8; f—g X 240]. 
adductor ridge is feebly developed and indistinctly limited ; the in¬ 
teriør side of the scutum is on the whole very feebly sculptured. 
The mandible (Fig. 76 f) has five teeth, the lower one being 
very small and almost confluent with the pectination of the lower 
angle. The maxilla has rather few spines and a short cutting 
edge; there is a small notch below the upper two spines, and be- 
low the notch about 8 spines are present. The maxilla is rather 
siender and small in comparison with the mandible. 
In cirrus I the rami are very unequal, the shorter one only 
half as long as the other ramus; the numbers of segments are 6 
and 13. In cirrus II the rami have 6 and 7 segments and only 
differ in the length of the distal segment. 
Cirrus III has again somewhat more unequal rami with 7 and 
10 segments; in shape it holds an intermediate position between 
the anterior two cirri with their haircovered bullate segments, and 
the posterior three cirri with their siender and rather long seg- 
