84 
J.E. Watson 
Monotheca pulchella, measurements (/<m) 
Stem 
internode length 
204-400 
diameter at node 
48-60 
length of apophysis (adcauline wall) 
52-64 
Hydrocladium 
length of athecate internode 
52-128 
width at distal node (shoulder) 
50-58 
basal length of hydrothecate internode 
164-200 
Hydrotheca 
length of abcauline wall 
100-148 
diameter of margin 
116-152 
Gonotheca 
length (excluding bent pedicel) 
560-696 
maximum width 
280-344 
Nematotheca 
length of base 
40-55 
diameter of cup 
32-50 
Remarks. Stranks (1993) considered microslide NMV F59054 
a probable syntype of Monotheca pulchella. I select this 
microslide as lectotype of Monotheca pulchella. 
The submarginal lobate cusps mentioned by Bale are 
clearly visible in the gonotheca of the type. On present 
evidence, M. pulchella is associated only with brown algae. 
This is in contrast to M. flexuosa, which is a common 
opportunistic species occurring on a wide variety of red and 
green algal and invertebrate substrates. 
The hydroid reported as Plumularia pulchella by Izquierdo 
et al. (1986) from the Canary Islands is probably Monotheca 
margaretta (see discussion in Calder, 1997), further supporting 
the contention that M. pulchella is endemic to Australia. 
Type locality. Queenscliff, Victoria, Australia. 
Known distribution. Victorian coastal waters. 
Distinction between Monotheca flexuosa and Monotheca 
pulchella. Monotheca pulchella (Bale, 1882) has often been 
confused by authors with Monotheca flexuosa (Bale, 1894). 
Although Bale clearly distinguished between the two species 
on the basis of M. pulchella having a robust septate stem, very 
short cauline internodes and hydrocladia midway along the 
internode, Totton (1930) reported infertile material from 
northern New Zealand as M. pulchella, presumably following 
Trebilcock (1928), who synonymised M. flexuosa in that 
species. Totton’s opinion was based on i) the specimens being 
twice the size of those described by Bale (for M. flexuosa ), 
some being half an inch in height (12 mm) and bearing 48 
hydrocladia, ii) the trophosome of M. flexuosa falling well 
within the range of variation of M. pulchella and iii) there 
being only slight apparent differences in the gonosome. His 
figure (fig. 58, p. 221) is clearly that of M. flexuosa. 
Later authors, such as Millard (1975) followed Totton but, 
with the exception of Millard, they did not provide figures of 
their specimens so the accuracy of their identifications cannot 
be confirmed. Watson (1973) examined Bale’s microslide 
specimens of both species in the collection of Museum Victoria, 
reporting the species to be markedly different and concluded 
that Totton was incorrect for the following reasons: i) height of 
the hydrocaulus is an unreliable character, ii) M. flexuosa has a 
more flexuous hydrocaulus than M. pulchella and iii) the 
gonothecae of the two species are markedly different. Medel 
and Vervoort (1995) misinterpreted Watson’s (1973) note on 
the submarginal gonothecal cusps of M. pulchella, and their 
description and figure is clearly that of M. flexuosa. Infertile 
material on green algae reported from New Zealand by Vervoort 
and Watson (2003) is also M. flexuosa. 
On present evidence, M. pulchella is endemic to southern 
Australia where it is associated only with brown algae. 
Monotheca spinulosa (Bale, 1882) 
Fig. 5A-G 
Plumularia spinulosa Bale, 1882: 30, pi. 15, fig. 8 — Bale, 1884: 
139, pi. 12, figs 11-12.- Bale, 1888: 783, pi. 19, figs 11-13.- Von 
Lendenfeld, 1885a: 475.- Bartlett, 1907: 43.- Warren, 1908: 320.- 
Mulder and Trebilcock, 1910: 123, pi. 3, fig. 9, 9a.— Mulder and 
Trebilcock, 1916: 81, pi. 11, fig. 4.— Briggs, 1918: 34,43.— Bedot, 1921: 
29.— Blackburn, 1937: 368— Blackburn, 1942: 116.— Pennycuik, 
1959: 180.- Ralph, 1961c: 109.- Millard, 1962: 301.- Millard, 1966: 
494.— Berrisford, 1968: 394.— Day, et al., 1970: 14,.— Watson, 1973: 
188, figs 54, 55.- Millard, 1975: 401, fig. 125 E-J.- Millard, 1978: 
196.— Watson, 1982: 107, fig. 4.11f-h.— Stranks 1993: 13. 
Monotheca spinulosa Stechow, 1921: 260.— Stechow, 1923: 
17.- Leloup, 1932: 160.- Millard, 1975: 401, fig. 125 E-J.- Millard, 
1978: 196- Hirohito, 1995: 278, fig. 96a-c.- Watson, 1996: 78.- 
Watson, 1997: 529.— Watson and Mclnnes, 1999: 111 — Watson 2003: 
243, 252.- Vervoort and Watson, 2003: 369, 374. - Watson, 2005: 
542.- Bouillon et al., 2006: 368. 
Plumularia spinulosa var. obtusa — Millard, 1957: 232. 
Monotheca spinulosa var. obtusa.— Stechow, 1923d: 225.— 
Yamada, 1959: 78. 
Material examined. NMV F59053, microslide, Queenscliff Victoria, 
Bale collection. Museum Victoria, nominated as probable syntype by 
Stranks (1993). 
Material in author’s collection : Stradbroke Island, south 
Queensland, on alga, depth 20 m, coll: J. Watson, 24 August 1975. 
Coniston Bay, Port Kembla, New South Wales, on bryozoan, depth 18 
m, coll: J. Watson, September 1975. Gabo Island, Victoria, on ascidian 
Herdmania grandis and red algae under ledges, depth 12 m, coll: J. 
Watson, 15 February 1973. Port Phillip Heads, Victoria, on red alga, 
depth 10 m, coll: J. Watson, 9 January 1984. South (20 km) of Cape 
Bridgewater, Victoria, on red alga, depth 100 m, coll: V. Johnstone, 
from fishing trawl, 16 May 1969. Port Noarlunga, South Australia, on 
red alga, depth 10 m, coll: J. Watson, 10 February 1976. Abrolhos 
Islands, outer reef. Western Australia, on red alga, depth 15 m, coll: J. 
Watson, 17 October 1986. Karapuki Island, New Zealand, coll: D. A. 
Staples 14 September 1975 on red alga. 
Description. Hydrorhizal stolons ribbon-like, flattened to 
substrate, outer flange with flexion joints in perisarc. Stems 
monosiphonic, to 5 mm high, basal stem region athecate, 
sometimes with two or three transverse nodes. Cauline 
internodes variable in length among colonies but typically 
moderately long and slender, straight to slightly curved, walls 
smooth, expanding slightly distally to apophysis, nodes 
