378 
not seen them, and the sizes of O.oe and O.ie I have found only 
very rarely. Also in dunedinensis (from type locality) they may be, 
at least, as small as O.os mm. Almost constantly the inner margin 
of the rim of the wheels was found to be very finely toothed, with 
ca. 100 teeth in the whole 
Fig. 59. Pieces of calcareous ring of Trochodota 
Dendgi (a), Tr. dunedinensis (b), and Tr. dunedi¬ 
nensis, var. microurna. (c), a. ^^/i, b. c. ^^/i. 
circumference; only once 
a wheel was observed with 
only ca. 70 teeth, the other 
wheels of the same spe- 
cimen having the usual 
number, and in one young 
specimen, with very few 
wheels (6 in the whole 
animal), all very small 
( 0.06 mm), there were only 
ca. 50 teeth. A coarse dentation as that figured by Den dy (PI. 
Vl.s.e) I never observed. The wheels are confined to the three 
dorsal interradii; only at the posterior end a few wheels may occur 
also in the two ventral interradii. The sigmata are very numerous, 
scattered, not arranged in papillæ. As pointed out by Per ri er 
(Op. cit.) they lie mostly transversally directed. 
Some additional information about this species may be given. The 
size of the specimens in hånd varies from ca. I .5 to 4.5 cm (in a 
well preserved condition). The skin is smooth, not papillate, except 
when strongly contracted. The colour of the living specimens was 
reddish-brown, small spots of this colour being still observable in 
some of the preserved specimens. An oval brownish spot at the 
base between each pair of tentacles. 
The anterior end is, in well preserved specimens, distinctly 
oblique in the dorso-ventral direction, the dorsal side being the 
more prominent. Also the dorsal tentacles are somewhat longer 
than the ventral ones. The mouth is a narrow slit, distinctly ex- 
centrical, adjoining the ventral side of the oral disk. Also the calcar¬ 
eous ring is distinctly oblique, parallel to the oral disk. The 10 pieces 
are, in accordance herewith, somewhat unsymmetrical; they are 
narrow, the radial pieces not perforated by the nerve (Fig. 59.b). 
The alimentary canal is stated by Den dy to exhibit three limbs, 
forming the usual S*shaped figure, being otherwise a good deal 
