Harris: The copepod genus Porcellidium 
107 
shape) with a narrow neck. About 3 A of its volume is occupied 
by the sperm mass, the remainder is a clear fluid. The 
guarding male re-couples with the newly metamorphosed 
female, as she emerges from the final moult, to deposit his 
spermatophore on her body. Usually it is placed on the ventral 
side of the females genital double-somite, but it may be 
placed anywhere on the dorsal or ventral part of the posterior 
body. Only part of this activity has been observed on one 
occasion with P. hormosirii (personal observation). Whilst 
clasping the female in the usual manner, the male pushed 
the hind region of its body forward under the female that 
appeared to be lifting her body as she does when irrigating 
eggs (Fig. 25E). The spermatophore, when deposited, 
adheres by its neck end (presumably by the congealed clear 
fluid) and remains attached for a relatively short period, an 
hour or so, before the empty case is lost. During that time 
the spermatozoa migrate to the spermathecae. When filled 
with sperm the spermathecae can usually be seen through 
the transparent cuticle of the nubile female before it hardens 
and colouration develops. The empty spermatophore case is 
lost long before egg-laying starts. Females receive only one 
spermatophore during their life span. 
Although the reproductive behaviour of Porcelloides 
tenuicaudus has not been observed and no coupled specimens 
were found in the very small sample available for study, there 
is a striking difference in the pattern of insemination between 
this genus and that outlined above. Mature males have typical 
antennules modified for clasping and, like all other members 
of the family, carry only one spermatophore. But the shape 
of the spermatophore and its placement on the female is 
quite different. It is common to see female P. tenuicaudus 
carrying two or more spermatophores. This must indicate 
that more than one male has deposited a spermatophore on 
the same female. 
The spermatophore, when deposited on the female is a 
large bean-seed or kidney-shaped (reniform) sack with a 
recurrent neck or duct running along the concave side. It is 
firmly attached to the dorsal surface of the female’s P5 lying 
on its side, (on some animals the recurrent duct can be seen 
lying in the gap between P5 and genital double-somite). 
The original drawing by Claus (1860) is ambiguous: he 
shows two spermatophores connected by ducts to the 
spermatheca, but it is not clear whether they are dorsal or 
ventral to the P5 limb. 
Perhaps the most significant feature in the reproductive 
biology of P. tenuicaudus is multiple deposition of 
spermatophores on the female. Claus (1860), Haller (1880) 
and Bartsch (1987) all show two spermatophores, one on 
each P5, but Bocquet (1948) states that there may be two, 
three or four. The female shown in Fig. 17A and Plate 
1G (p. 67) has two spermatophores attached to the P5s, 
but a specimen of Porcelloides tenuicaudus in the NHM, 
London carrying eggs has four spermatophores attached 
(Fig. 25D), (personal observation). Because a male only 
produces one spermatophore, the presence of more than 
one on a female implies that the female has received them 
from more than one male. The fact that a female of other 
species only receives one spermatophore during her life 
time (immediately after metamorphosis) and males never 
couple with adult (egg bearing) females implies that the 
normal mate guarding behaviour and the stimulus inducing 
release of the spermatophore is different in Porcelloides to 
all other species. 
Spermatophores remain attached for a long period. This 
is indicated by two facts. First empty spermatophore cases 
are sometimes covered in the same epizoic micro-organisms 
(diatoms, suctorian protozoa etc.) found on the female’s 
body and second, empty cases are still present on females 
carrying eggs. 
These reproductive peculiarities appear to be of 
more fundamental significance than normal apomorphic 
differences and set Porcelloides apart from all other 
genera. This might be considered grounds for splitting 
the family into two sub-families, but a far more detailed 
study of the reproductive biology of Porcelloides is 
necessary before such a step is taken. Except for its own 
apomorphies, Porcelloides shares all the characteristics of 
the Porcellidiidae. 
Acknowledgments. I am grateful to Dr G. A. Boxshall for 
allowing me to examine the slides and specimens of Porcellidiidae 
in the Natural History Museum, London and for his helpful 
discussion and interest in Australian species. I also wish to thank Dr 
J. M. Holmes for allowing me to examine the porcellidiid material 
in the National Museum, Dublin and for suggesting I should obtain a 
permit to collect specimens from Loch Hyne, County Cork, Ireland 
where I found Porcelloides scutatus (Claus, 1889). I am deeply 
indebted to the various referees for the valuable, time spent on 
making comments, corrections and interpretation of the ICZN mles. 
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