Notes on Indo-Pacific Scleractinian Corals 
Parts I and II 
Part L Oryzotrochus, a New Genus of Turbinolian Coral 
John W. Wells^ 
In 1954 the writer spent a few days studying 
part of the coral collections of the Australian 
Museum. Among much undetermined mate- 
rial was a lot consisting of two species of very 
small turbinolian corals from a dredge haul 
(source unknown) made at the northern end 
of the Great Barrier Reef. One species was 
Holcotrochus scriptus Dennant 1902, a most pe- 
culiar form previously recorded only from the 
Lower Miocene and Pliocene of South Aus- 
tralia and from depths of 38-185 meters off 
South Australia. It was represented by some 
20 individuals, 1 of which is illustrated in 
Figures 6 and 7. The other species, represented 
by 100 specimens, mostly more or less dam- 
aged, proved to be a new turbinolian genus, 
here called Oryzotrochus in allusion to its re- 
semblance to a rice grain. 
Special thanks are due to F. J. McNeill of 
the Australian Museum for permission to re- 
tain several specimens for description. 
Family CARYOPHYLLIIDAE 
Subfamily TURBINOLIINAE 
Oryzotrochus gen. nov. 
Small, solitary, free, conical corals. Wall 
imperforate, externally costate with promi- 
nent, high, smooth costae. Septa exsert, 
smooth margined, lightly granulated laterally. 
Pali absent. Columella small and styliform. 
This genus is obviously very closely allied 
to the well-known Tertiary (Eoc.-Mioc.) 
genus Turhinolia,^ from which it is distin- 
guished only by the absence of mural perfora- 
tions or external intercostal pits. The more 
apparent differences from other conical tur- 
binolians are brought out in the following 
artificial key. 
A. Wall perforate or with deep intercostal pits: 
1. Pali absent: 
a. Columella spongy Bothrophoria Felix (U. Cret.) 
b. Columella styliform: 
aa. Costae smooth Turbinolia Lamarck (Eoc.-Mioc.) 
bb. Costae hispid Batotrochus Wells (Rec.) 
2. Pali present: 
a. 1 crown of 6 before second cycle; 
costae smooth Conocyathus d’Orbigny (Eoc.-Rec.) 
b. Pali weakly developed; 
costae hispid Trematotrochus Tenison-Woods (Olig.-Rec.) 
B. Wall imperforate: 
1. Paliform lobes absent Oryzotrochus n.g. (Rec.) 
2. Paliform lobes present Notocyathus Tenison-Woods (Eoc.-Rec.) 
2 Turhimlia australiensis Gardiner 1939 {Discovery 
Reports, vol. 18, p. 332, pi. 21, figs. 1, 2), from Port 
1 Department of Geology, Cornell University, Jackson, N. S. Wales, is Conocyathus zelandiae Duncan 
Ithaca, N. Y. Manuscript received February 17, 1958. 1876. 
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