237 
doubted byVaughan (1905) and G a rd i n e r (1909). It is a more 
primitive form than the other species of Halomitra on account of 
the faet that the maiority of its secondary calicles are very incon- 
spieuous. The number of comparatively large secondary calicles in 
one of the specimens (fig. 135), however, gives to this species 
almost the same appearance as that of young forms of the other 
species of Halomitra. 
Halomitra philippinensis Studer 
(Fl. VIII, figs. 93-98, PI. IX, ligs. 105, 106, 111, 118, 119, 121, PI. XI, figs. 127 and 129). 
Halomitra tiara Studer 1901. 
Halomitra concentrica Studer 1901. 
Halomitra philippinensis Studer 1901. 
Halomitra philippinensis Gardiner 1909. 
Halomitra pilens van der Horst 1921. 
Halomitra tiara van der Horst 1921. 
Halomitra lomvinae van der Horst 1921. 
Localities: D. Exp. t. Kei I si.: Amboina, 0 —2 m, 1 ex.; Banda, 0—25 
m, 122 ex. 
I classify with this species all specimens of Halomitra with 
almost smooth costal spines in my collection. The corallum is thin, 
in those specimens in which the central calicle is present it is 
mueh larger than the secondary calicles, the septa and costae are 
radially placed round the centre, at least in the marginal part of 
the corallum, the theca is perforated. The costal spines are not 
altogether smooth, they are provided with a few small granulations 
and have therefore a somewhat rough appearance, their apical part 
is ofteri slightly ramified (fig. 129). This characteristic is also 
mentioned by Studer ^ov H. philippinensis and chiefly on account 
of this feature I have identified them with this species. After Stu¬ 
der the columella is rudimentary and spongy in the bottom of the 
calicles, in my specimens the columella is often visible as a mass 
of irregular trabecula and in other calicles it is almost completely 
wanting. 
The four species of Halomitra described by Studer are very 
closely allied, as already Gardiner (1909) remarks. In my opinion 
at least three of Studer’s species, viz. tiara, concentrica and 
philippinensis, belong to the same species, whilst H. pilens Studer 
