227 
prominent septa has a notch in which two neighbouring septa of 
less prominence have fused and in this way the centre of a new 
calicle is formed. In Herpolitha Umax the new calicles originate in 
quite the same way. Some of these very young calicles are clearly 
visible in van der Horst’s fig. 5. 
Herpolitha Umax (Esper). 
(PI. VIIl, figs. 78-85, and PI. IX, fig. 117). 
Herpolitha Umax Milne Edwards and Haime 1851. 
Herpolitha Umax van der Horst 1921. 
(Other synonyms are given by van der Horst 1921. Cp. below for 
Madrepora pilens Pallas\ 
Localities: D. Exp. t. Kei I si.: Banda, 0—25 m, 50 ex.; Ambon, 0—2 
m, 2 ex. 
In his paper on the Fungid corals of the Siboga Expedition 
van der Horst (1921) suggests that the species now generally 
known under the name Herpolitha Umax as a matter of faet has 
a right to the name of Herpolitha pilens (Eli. and Sol.). The figure 
of Ellis and Solander indeed represents a form of Herpolitha, 
but we have first to discuss the forms described as Madrepora 
pilens before El lis and Sol ander to make out to which genus 
the original Madrepora pilens belongs. 
In the tenth edition of his Systema Naturae (1758) Linnaeus 
gives a short description of a corallum called by him Madrepora 
Pilens. The form defined here under this name is based on the 
specimen represented on Tab. LXXXVIII, fig. 3 of Rumphius’ 
Herbarium Amboinense, Pars VI (1750), which is cited in Linnaeus’ 
diagnosis. As may be concluded without any doubt from Rumphius’ 
figure and description, the form dealt with (the Mitra polonica) 
belongs to the present genus Halomitra (or Ddderleinia) and there- 
fore the specific name „pilens'' has to be retained for a species of 
this genus. Fig. 2 of the same plate in Rumphius’ work repre¬ 
sents an oblong corallum, probably belonging to the present genus 
Polyphyllia, which was called by him „Umax saxea". 
In the twelfth edition of the Systema Naturae (1760) Lin¬ 
naeus also only refers to Rumphius’ Tab. LXXXVIII, fig. 3 as 
a form corresponding with his Madrepora Pilens. 
Shortly afterwards (1761) Seba described and figured a number 
15* 
