261 
ton) is in reality specifically distinet, and corroborates the state- 
ments ofjennings (1915) that Pollicipes Darwini is synonymous 
with Mitella sertus. Jennings moreover considers the latter name 
as a synonym of Mitella spinosa (Quoy et Gaimard); my material 
does not allow me to follow up this question; my specimens quite 
agree with Mitella sertus, and differ from Mitella spinosa, accord- 
ing to the dates given by Gruvel and Darwin. 
Characteristic of the species are the small latera, which in faet 
only look like rather well developed peduncle spines. Only the 
rostrum is very strongly developed, its distal half or more pro- 
jecting like a horn. — The mouth feet are very characteristic and 
agree with Darwin’s descriptions (Fig. 21c, d). The man dible 
has three principal teeth, the second standing below the middle of 
the cutting edge; between this and the first principal tooth two 
secondary, smaller teeth are inserted, and a very small accessory 
tooth may also be indicated between the second and third main 
teeth. The lower angle is strongly pectinate; the entire mandible 
is almost perfeetly destitute of finer hairs. The maxi 11a has a 
straight cutting edge without exeavations or notehes; the upper spine 
is only little larger than the 
crowded spines of the edge; 
just above the lower angle 
one tuft of bristles is evident. 
Only very few finer hairs are 
seen near the cutting edge. 
Two quite small specimens 
were present in the material 
(Fig. 22). Of the primordial 
valves scutum has evidently 
already a characteristic shape; 
it is typically triangular with 
a broad, almost straight base, 
and differs strikingly from the 
trapezoid scuta of the other 
species with their strongly 
curved basal margins. In 
both specimens the difference 
between the primary plates 
Fig. 22. Mitella sertus from Hen and Chicken 
Island, N. Z. a subearina only just indic¬ 
ated, complele animal; b also subrostrum 
well developed (peduncle only partlv drawn, 
of the same length as the capitulum). [x 23]. 
