282 PERCY SLADEN TRUST EXPEDITION, 
The genus appears to me to be most nearly related to the Repanda-group of Fungia, 
coming closest to F. granulosa, Klz. It has two species—D. irregularis below, and 
D. robusta= Podabacia robusta, Quelch (‘ Challenger’ Report, p. 140, pl. vi. fig. 5). 
The latter was founded on a single specimen from Amboina, now in the British Museum. 
[t is a regenerated disc, its original piece being clearly visible. 
The genus is named after Prof. Ludwig Déderlein, the great merit of whose work on 
Fungia 1 have perhaps been rather tardy in recognising. 
21. Déderleinia irregularis, Gardiner. (Plate 39. figs. 27, 28.) 
Halomitra irregularis, Gardiner, Proc. Zool. Soc. 1898, p. 528, pl. 43. figs. 1, 2. 
Halomitra (Podabacia) irregularis, Studer, Zool. Jahrb., Bd. xiv. p. 415. 
This species was founded on two specimens from lagoon-shoals off Funafuti. The 
smaller is now figured for the first time. The squarish area on its underside, marked off 
by a groove, is not, as I previously suggested, its scar of detachment, but represents the 
original fragment of a larger corallum from which the present specimen has regenerated. 
The larger specimen shows a similar but larger fragment. 
D. robusta is evidently closely related to this species, but its wall is much more freely 
perforated, and its costs are quite distinct in rows of spines over the whole of its under 
surface, not hidden by spines as in my species. Its calicles, too, are rather more open, 
showing the fusion together of their septal edges in small columellee. 
VI. Genus HERPOLITHA. 
Duncan, Journ. Linn. Soc., Zool. xviii. p. 145. 
The following account deals with three species of the genus, which was almost 
certainly derived from the Scutaria-group of Fungia. The specimens of H. limax give 
further evidence that the adult is, as in Fungia, an anthocyathus derived from a 
trophozooid by detachment *. Of other described species of the genus I have removed 
H. simplex to the genus Fungia; it is clearly allied to the Hehinata-group ft. H. stellaris, 
Ehrb., is almost certainly a synonym of ZH. limax, but H. interrupta may be a good 
species. The others—H. stricta, Dana, and H. ampla, Agassiz (Verrill)—are insulficiently 
described for identification. 
The genus is restricted to the Indo-Pacific, being apparently abundant in the East 
Indies. It has not yet been obtained from the Chagos or Seychelles regions. 
22. Herpotitha foliosa (Ehrb.). (Plate 36. figs. 14,15; Plate 37.) 
Klunzinger, Die Korallthiere des Rothen Meeres, i. p. 68, t. 8. figs. 4, 5. 
I have five specimens before me which I refer to this species. It differs from H. limax 
in being much more finely built, thinner and less heavy, and in its wall being much more 
perforate, the perforations being small slits between the coste. It has rather lower, 
* Vide Vaughan, Proc. U.S. Nat. Mus. xxviii. p. 380. 
T See under Fungia simplex, No. 10 above. 
