J.E. Watson 
beside apophysis on first stem internode, body barrel shaped, 
distally truncated, walls smooth to weakly undulated, aperture 
terminal, transverse, closed by a sheet of tissue. Female 
gonotheca unknown. 
Monotheca togata, measurements (/tm) 
Hydrorhiza, width 
72-80 
Stem 
length of cauline internode 
300-360 
width at subnodal septum 
76-80 
length of apophysis (adcauline) 
40-50 
Hydrocladium 
length of subhydrothecal chamber adcauline 
100-130 
length of athecate internode 
30-40 
width at distal shoulder 
44-64 
length of hydrothecate internode (along 
base) 
180-220 
Hydrotheca 
depth, floor to highest point on margin 
192-224 
width across margin (frontal view) 
186-200 
Nematotheca 
length of base of cauline 
36-52 
width of cup 
26-40 
length of base of median inferior 
28-32 
width of cup 
48-52 
width of cup of lateral 
30-44 
Gonotheca 
length of pedicel 
35-40 
length excluding pedicel 
1040-1260 
distal diameter 
600 
Remarks. The cauline and axillar nematothecae are often 
absent. The frontal position of the cauline apophysis causes the 
hydrocladia and hydrothecae to twist forward during microslide 
mounting, which tends to obscure some structures. 
This is first description of the gonotheca of Monotheca 
togata. The species is closely related to M. hyalina in size of 
stems and the cowl-shaped hydrotheca with a hemispherical 
margin. The distinctive adcauline apertural peak of M. togata 
distinguishes it from M. hyalina. 
Monotheca togata (NMNZ BS834), was reported from 
East Cape and Ranfurly Bank, New Zealand, by Vervoort and 
Watson (2003). However, the material differs from the 
Australian species in having i) no axial hydrostatic pore, ii) a 
much smaller hydrocladial median inferior nematotheca, and 
iii) shorter cauline and hydrothecate internodes. In contrast to 
the epiphytic Australian species, the New Zealand material is 
epizootic on Synthecium suventricosum and Halopteris 
campanula. These structural and substrate preferences may 
indicate the New Zealand material is a different species, but 
until more is known, the material is here doubtfully referred to 
M. togata. 
Type locality. Pearson Island, Great Australian Bight. 
Known distribution. Southern Australia to Western Australia, 
?New Zealand. 
Key to species of Monotheca in Australia 
1 Hydrotheca cup or bowl shaped.3 
- hydrotheca not this shape.2 
2 Hydrotheca scoop, cowl or hood shaped.6 
3 Hydrotheca with conspicuous abcauline flange. 
. Monotheca amphibola 
- hydrotheca with inconspicuous abcauline flange or no 
flange.4 
4 Hydrocaulus flexuous, gonotheca barrel shaped with 
distal aperture. Monotheca flexuosa 
- hydrocaulus robust, gonotheca not barrel shaped.5 
5 Aperture of gonotheca oblique with submarginal lobes. 
. Monotheca pulchella 
6 Hydrotheca with adcauline intrathecal septum.7 
- hydrotheca without intrathecal septum.9 
7 Intrathecal septum inconspicuous. Monotheca obliqua 
- intrathecal septum well developed.8 
8 Hydrocladium with terminal spine. 
. Monotheca spinulosa 
- hydrocladium without terminal spine. 
. Monotheca australis 
9 Hydrotheca subhemisphaerical, margin hooded.10 
10 Hydrotheca with distinct adcauline marginal peak. 
. Monotheca togata 
11 Hydrothecal margin without adcauline peak. 
. Monotheca hyalina 
Acknowledgements 
I thank the many colleagues who generously spent time 
underwater with me over the years and the much appreciated 
helpful criticism of the reviewers of the manuscript. 
References 
Anonymous 2004. Catalogues of the collections in the Showa Memorial 
Institute, National Science Museum, Tokyo. No. 2: 1-139. 
Bale, W. M. 1882. On the Hydroida of south-eastern Australia, with 
descriptions of supposed new species, and notes on the genus 
Aglaophenia. Journal of the Microscopical Society of Victoria 2: 
15-48, pis 12-15. 
Bale, W. M. 1884. Catalogue of the Australian hydroid 
zoophytes. Australian Museum, Sydney. Pp. 198, pis 1-19. 
Bale, W. M. 1888. Some new and rare hydroids in the Australian 
Museum. Proceedings of the Linnean Society of New South 
Wales: 745-799. 
