200 THE ECHINODERMS OF TORRES STRAIT. 
have included in the following list all species known from both the eastern and 
western coasts of tropical Australia which have not already been given in lists 
1 to 3. There are 64 such forms shown in list 4. 
List 4.—Species of Tropical Australian range. 
Capillaster multiradiata. 
Comatula pectinata.* 
purpurea.* 
rotalaria. 
solaris.* 
Comaster belli. 
multifida. 
noveguiner. 
Comanthus briareus. 
Zygometra elegans. 
microdisca. 
punctata. 
Heterometra crenulata. 
Amphimetra discoidea. 
jaquinoti. 
Stephanometra indica. 
Lamprometra gyges.* 
Oligometra carpenteri. 
Oligometrides adeone. 
Tropiometra afra.* 
Astropecten zebra.* 
Archaster typicus. 
Luidia maculata. 
Iconaster longimanus. 
Stellaster incei. 
Anthenea tuberculosa. 
Oreaster gracilis. 
nodosus.* 
Hacelia helicosticha. 
Nepanthia brevis. 
Metrodira subulata. 
Ophiothrix galatezx. 
hirsuta.* 
martensi australis.* 
melanogramma. 
melanosticta. 
punctolimbata. 
stelligera.* 
striolata. 
Ophiomaza cacaotica.* 
Ophiothela dane. 
Pectinura yoldii. 
Ophiarachnella infernalis.* 
Ophiolepis superba.* 
Prionocidaris bispinosa. 
Nudechinus darnleyensis.* 
Tripneustes gratilla.* 
Salmacis sphzroides. 
virgulata alexandri. 
Temnotrema bothryoides. 
Breynia australasiz. 
Echinocardium cordatum. 
Synapta recta. 
Thyone mirabilis. 
sacellus. 
Pseudocucumis africanus.* 
Actinocucumis typicus. 
Pentacta doliolum. 
tuberculosa. 
Holothuria fuscocinerea.* 
Holothuria modesta.* 
Stichopus variegatus.* 
Actinopyga echinites. 
miliaris.* 
The forms occurring in the Murray Islands area are indicated in the above 
list by asterisks, and it is surprising to find that there are only 20 of these. More- 
over, only half a dozen of the 20 are at all common at Mer, and 4 we did not meet 
with there at all. It is perhaps of some significance that only 5 of the 20 species 
occur at Fiji or Samoa. Only 8 of the 20 are known from the eastern end of New 
Guinea or the islands east and north thereof. It seems reasonable, therefore, to 
suppose that most of these 20 species in question have reached the Murray Islands 
region from the west through Torres Strait and are comparatively recent arrivals 
there. This conclusion is less likely to be true, however, for the most widely dis- 
tributed species, such as T'ripneustes gratilla. 
Somewhat larger than the Australian group of species which is so poorly 
represented at Mer is what may be called the Barrier Reef group, which forms 
about half of the Murray Islands fauna and extends southward along the coast 
of Queensland, often to Port Curtis and occasionally to New South Wales. This 
group contains 73 species, as shown in list 5. 
Examination of this list reveals a very noteworthy fact, namely, that whereas 
70 of the 73 species are known to occur in the East Indian region, not one is known 
from the vicinity of Thursday Island and only 7 are found either at the Aru or Kei 
Islands or in the Arafura Sea. Moreover, 40 of the forms listed have been recorded 
from the eastern New Guinea-New Caledonia area and 61 from the islands of the 
tropical Pacific west of latitude 160° E. There is no doubt that imperfect explora- 
tion of the New Guinea-New Caledonia area is the reason why fewer of the species 
are known there than from the islands further east. There are 4 species among the 
73 which we did not find at Mer, but it is quite likely they occur there; they are 
