250 
first two smaller teeth; the excavation between the lower of these 
latter and the second large tooth is armed with two or three di¬ 
minutive spines. The sinus between the lower teeth, and the lower 
angle of the mandible are strongiy pectinate; the lower angle is 
not very prominent although rather pointed. The sides of the mand¬ 
ible are covered by fine hairs near the cutting edge. 
The maxi 11a has a strong upper spine; there is no notch nor 
excavation along the cutting edge; this latter is straight and armed 
with spines, shorter and slenderer than the upper spine. The lower 
corner is a little prominent and carries a small brush of bristles. 
Some few fine hairs are seen on the sides of the maxilla near the 
cutting edge. 
In the specimen I from Plimmerton two males were found 
attached to the inner edge of the scuta at the apex of the rostum. 
They are both a little damaged from the preparation, but one of 
them (Fig. 13 d) gives a good idea of the general features, being 
only very little damaged on one side. The male has a capitulum 
skeleton consisting of carina, terga, scuta, and rostrum; in the spec¬ 
imen figured an accessive latus is present on one side. The latter 
may of course be an exceptional irregularity, but it also may be 
regarded as evidence of a tendency to variation. The difference 
in shape of the uninjured plates of the two males observed 
evince a tendency towards variation in the capitulum plates quite 
parallel to that found in the hermaphrodite. 
The males have a well developed peduncle. 
None of the descriptions hitherto published of the Mitella- 
species covers the animals brought home by Dr. Mortensen. In 
some respects it seems to come near to Mitella (Pollicipes) Darwini 
Hutton; the latter species nevertheless apparently differs in the 
more curved carina; also Gru vel speaks of „écailles pédoncul- 
aires“ in this species, a designation not likely to cover the spines 
of Protomitella paradoxa. Recently J e n n i n g s (1915) has more¬ 
over identified Pollicipes Darwini as synonymous of Mitella sertus, 
a species which markedly differs from Protomitella paradoxa. — 
Of the Slipper Island specimens, the most regular one (Fig. 13 c) 
decidedly recalls the typical Mitella. In this specimen no accessive 
