32 
F.C. Holmes 
Figure 3. Peribrissus janiceae sp. nov. holotype NMV P316528. A-D and F, anterior, right lateral, posterior, adapical and adoral views; E, detail 
of apical disk; G, oblique left lateral view of semipetalious fasciole crossing interambulacrum 4, plates 7a, 8a, 9a and 9b; H, detail of peristome, 
labrum and phylodal plates; I, detail of junction between marginal and semipetalous fascioles on interambulacrum 1, plate 4b. Scale bars = 10 mm 
unless otherwise shown. 
Tubercles in ambulacra II and IV first appear on plates 3a and 
b, and in I and V on plates 4a and b. By plates 5a and b, the size 
and spacing generally matches that of adjacent interambulacra. 
Largest tubercles with an approximate areole diameter of 1.0 
mm occur on interambulacra 1 and 4 adjacent to adoral edge of 
plates 2a and b, aborally on plate 1, and along the adradial 
suture line between ambulacrum III and interambulacra 2 and 
3 from the marginal fasciole to the apical disk. These tubercles 
have a perforate mamelon and crenulate platform but appear to 
lack a scrobular ring. Because of the very close spacing of these 
tubercles, miliary granules occur mainly towards the peristome 
and between the periproct and marginal fasciole in 
interambulacrum 5 where the spacing between the larger 
tubercles increases. They also occur around the apical disk. 
A well-defined marginal fasciole occurs just above the 
sloping ambitus, dipping sharply below the periproct posteriorly 
but crossing ambulacrum III anteriorly slightly below the 
ambitus at about 25%TH (see fig. 2). The semipetalous fasciole 
is only marginally indented between the posterior paired petals 
and crosses interambulacra 1 and 4 on plates 8/9 before 
descending transversely to join the marginal fasciole at right 
angles, posterior to the angle of the anterior paired petals (see 
fig. 31). Although continuous, fasciole widths vary but maintain 
a fine tubercule (granule) density of about 100-120 per mm 2 . 
