Records of the Australian Museum (2014) Vol. 66 
pinnate at posterior apex (Fig. 17D), medial edge straight, 
bordered with fine setules along entire length, lateral edge 
divergent, without setules, extends as far as level of (3 seta, 
bevelled edge 4 x length of medial edge, bordered with fine 
setules, a and |3 setae inserted proximally, terminal seta T1 
small inserted about 54 down bevelled edge, y and T2 about 
l A way down bevelled edge, T3 absent. Antennule, segment 
1 seta pinnate (Fig. 17F), no plumulose setae on segment 
2. Setation of mouthparts and ambulatory limbs typical of 
family. Basis and segment 1 of antenna endopod with setules 
along medial border, exopod with five plumulose setae and 
one plain spinous seta, segment 2 of endopod with one small 
and two longer lateral setae (1 pinnate), geniculate setae 
with distal part plain, claw comb-like (Fig. 18A). Anterior 
lobe of mandibular palp with small patch of ventral setules 
(Fig. 18E). Gnathobase of maxillule precoxa (Fig. 18B)with 
five plain and three pinnate setae plus two lateral geniculate 
setae, endite on coxa and two endites on basis with four setae 
each, endopod with six setae, exopod with one plain and one 
bulbous seta. Proximal endite on syncoxa of maxilla (Fig. 
18H) with four setae, distal endite with one seta, spatulate 
seta on basis with comb-like edge, endopod with three 
biserrulate and two multi-serrulate setae. Maxilliped coxae 
touch in midline, basis with fimbriate border and fimbriate 
process (Fig. 18D). No peg area on PI endopod, endopod 
1/w = 1.05, terminal claws of endopod lamellate (Fig. 19A). 
P2 endopod PA times length of exopod (Fig. 19B), external 
seta on exopod segment 1 short, terminal segment of endopod 
with strong, serrate spinous seta plus three plumose setae. 
P3 (Fig. 19E) spinous seta on segment 2 of endopod finely 
serrulate, shorter than endopod (0.75:1), large spinous seta 
on terminal segment slender, serrate, longer than endopod 
(1.4:1). P4 endopod % length of exopod (Fig. 19F), external 
seta on segment 1 of exopod as long as segment 1, spinous 
seta on endopod segment 2 and first (internal) spinous seta 
on segment 3 both long, thin and finely serrulate. P5 (Fig. 
19D) baseoendopod with small plain external and serrulate 
internal seta, exopod broad, ovate (*w/l = 0.45), bordered 
along external edge with short setules, dorsal surface with 
pits except for medial edge which has a reticulate pattern, 
two large pinnate dorsal setae plus two plain setae at apex. 
P5s reach to posterior extremity of caudal rami. (* Width of 
P5 at level of lateral seta). 
Adult males (Fig. 20A). Colour, body shape, hyaline 
border and dorsal pits as for female. Anterior edge of 
cephalosome rounded, slightly truncated, rostrum with 
ventral keel, only visible from ventral view, projects as 
convex bulge in midline (Fig. 20C), lateral angle of antennule 
socket with conical projection. Caudal ramus short, almost 
quadrate (Fig. 20B), lateral edge convex with setules down 
posterior % y medial edge straight with fine setules down 
length, a and (3 setae short (% width of ramus), T1 pinnate, 
short, slightly recessed, T2 very short, plain, T3 absent, T4 
pinnate, close to medial comer, posterior border with fine 
setules, dorsal surface of rami with fine reticulate pattern. 
Antennule short, 28% of cephalosome width with dactylus 
fully extended, (Fig. 20A, H), segment 1 expanded medially 
to touch its fellow in front of rostrum, segment 3 with anterior 
process bearing 5 and 5' setae, and n series, segment 4 with 
proximal triangular coupling denticle, large denticulate pad 
and bicuspid distal denticle (Fig. 20F), dactylus (segment 
5) cylindrical (’A length of segment 3+4), hooked distally, 
segment 6 small, fused to segment 5. Ambulatory limbs differ 
from female as follows. Endopod of P2 with two plumose 
terminal setae (Fig. 19C). P5 exopod trapezoid (Fig. 20D), 
length of terminal setae < l A of P5 lateral edge, first (lateral) 
seta narrower than rest of terminal setae, ventral row of six 
or seven setules at base of each terminal seta (Fig. 20G). 
Developing spermatophore ^-shaped (Fig. 20E), reniform 
(kidney or bean-shaped) with recurrent duct when fully 
formed and deposited on female P5 (Fig. 18C). 
Remarks. Only a few isolated specimens of Porcelloides 
tenuicaudus have been found after extensive sampling on 
the West coast of Scotland and Pembrokeshire, Wales, which 
suggests the animal’s preferred habitat was not sampled. 
The typical dorsoventral flattened body of most porcellidiid 
species is correlated with life in fast flowing or turbulent 
waters of the littoral zone where the shape of their body 
enables them to hold on tenaciously to the substratum. 
When P. tenuicaudus is subjected to fast flowing water (i.e., 
a jet from a pipette) it rolls into a ball and detaches from 
the substratum (personal observation). This suggests that 
its normal habitat may be in deeper water away from fast 
flowing currents. Haller (1879) dredged his Porcellidium 
ovatum (= Porcelloides tenuicaudus ) from 80-150 metres 
and Brady dredged it from 10 fathoms near the Scilly Islands. 
Distribution. In the present study specimens were collected 
from the following algae. Himanthalia elongata at Castle 
Bay, Dale, Pembrokeshire (51°42'N 5°10'W), (4 \ V. A. 
Harris, 1974. From Chondrus crispus , holdfasts of Laminaria 
saccharina, and stones covered with pink Lithothamnion, 
in the sublittoral at Clachan, Shiel Sound, Oban, Scotland 
(56°19'N 5°35'W), (4 ??, 2 88), V. A. Harris, 1974, 1987. 
In literature ( cf. Lang, 1948) it is reported from Shetland 
Islands, Ireland, Scilly Islands, W coast of France and 
Mediterranean Sea. 
Porcelloides scutatus (Claus, 1889) comb. nov. 
Figs 21-24 
Porcellidiumscutatum Claus, 1889: 34, taf., VIII, abb., 9-18. 
Porcellidium ovatum. —Lang, 1948: 442; Geddes, 1968: 14; 
Holmes & O’Conner, 1990: 66; Huys et ah, 1996: 307, 
123; Wells (2007): 79. 
Material examined. Spirit material and prepared slides in 
NMI, Dublin, collected by D. Minchin and J.M.C. Holmes 
from Loch Hyne (Ine), Co. Cork, Ireland (9° 15'W 51 °30'N), 
(see Appendix 2). Living material, used for measurements 
and the following description, was collected from red alga 
{IGelidium sp.) Loch Hyne, Co. Cork, Ireland and identified 
from species specific characters in Claus’ 1889 description 
of Porcellidium scutatum. 
Specimens of Porcelloides scutatus (4 9$, 5 SS and 
five dissections mounted on slides) have been deposited at 
NHM, London, V. A. Harris, 1997. 
Diagnosis. Hyaline border appears striated; about l A female 
caudal ramus lies in arch of genital double-somite; female 
caudal ramus trapezoid, apical angle 50°, bevelled edge 
almost equal in length to lateral edge, T1 and y setae at 
lateral corner of bevelled edge, T2 normal, T3 very thin, 
inconspicuous, no setules along medial edge (Fig. 22H); 
female P4 with massive serrated spinous setae on segments 
2 and 3 of endopod (Fig. 23B); ventral falciform ridge on 
female P5 undulating (wavy), apical seta pinnate (Fig. 22D, 
