56 
The Queensland Naturalist. 
VoL. 2 
Sargassa may cover extensive areas, a well developed sargas- 
setum occurring on the northern side of Moffat’s Head, and 
corresponding to the hormosiretum of the Sydney district. 
Cystiphyllum muricatum and Dictyota dichotoma are very 
abundant. Amongst other sea-weeds occurring in this region 
and extending into deeper water are Chondrococcus harveyi, 
Plocamium hamatum, Halimeda tuna, Cauleypa spp., Chmto- 
morpha cerea, Sphacelaria ? biradiata, Pachydictyon, Chondria 
dasyphylla,^ Derhesia claviformis, Gymnosorus variegatus, 
Pqdina pavonia, Codium elongatum and C. adhcerens, Peys- 
sonnelia, Lithothamnion, Melobesta, Dilophus, Ceramium spp., 
Laurencia concinnia, etc. 
Tiie characteristic animal of the zone is the variable 
and prettily-coloured Onithochiton quercinus. Associated with 
it are two rather uncommon chitons, Plaxiphora pceteliana 
and Rhyssoplax miles, the last being rare. Small specimens 
of Tetraclita rosea are common. Balanus nigrescens occurs 
in the lowest inter-tidal region. Amongst the gastropods, 
the commonest are Hemitonia aspera, Thais succincta, Drtipa 
marginalba and Cellana variegata. Siphonaria. scabra some- 
times extends its range downwards to this region. The 
ascidian Cynthia prcepiitialis is not uncommon, especially 
on the south-west of Caloundra Head, but it is not a dominant 
form there as it is on the Tweed Heads rocks. 
Amongst other members of the fauna, one may mention 
the occurrence of various sponges {Clathria, Sycon, etc.) ; 
Ophiuroids ; Hy droids [Diphasia, Sertularia, Campamdaria, 
Pasythea, Plumularia, etc.) ; Polyzoa {Memhranipora, Cateni- 
cella, Electra, etc.) ; Pycnogonida (on Hydroids and Cateni- 
cella) ; Polychaeta {Eunicids,' Nereids, Polynoids) ; Amphipods 
[Orchestia^ spp.) ; the peculiar Kelp crabs {Naxia tumida), 
which plant algse on the carapace, and thus come to resemble 
the sea-weeds, amongst which they slowly creep ; and the 
beautiful Keljj shell [Caniharidus eydmius), which lives on 
Sargasstm. 
Laurencia obtusa area. — Forming a fringe along the 
upper edge of the Sargassum horizon, there is in places a well- 
defined area characterised by the presence of a red sea-weed 
Laurencia obtusa, which at some seasons is almost green 
(November-December), while at others (March) it is purplish 
red. Its flora comprises also Caulerpa nummularia and other 
species of the genus, Entermorpha intestinalis, Chauvinia corii- 
folia, Lithothamnion, stunted specimens of Dictyota dichotoma, 
Sargassum leptopodum and Cystiphyllum muricatum. Some- 
times (March) Ceramium clavulatnm is very common. Chaeto- 
morpha and Ulva appear at certain times. 
* I'bis is a (delicate plumose red seaweed with large fruits (NovemDer-January), 
named for the late Mr. F. M. Bailey, by Kew authorises as C. dasyphylla, My 
specimens have not allowed Mr. Lucas to accurately determine it [Chondri or 
Dasya). It resembles W raneelia plumosa in its colour and general form. 
