128 THE VOYAGE OF H.M.S. CHALLENGER. 
Genus 6. Psammocora, Dana. 
Psammocora, Dana, Zoophytes, p. 344. 
Pe Milne-Edwards and Haime, Cor., iii. p. 219. 
* Duncan, Rev. Madrep., p. 192. 
Recent investigation has shown that this genus must be placed under the Fungida 
and not under the Perforata, as in the system of Milne-Edwards and Haime. 
Three species are in the collection. 
1. Psammocora exesa, Dana. 
Psammocora exesa, Dana, Zoophytes, p. 348, pl. xxvi. fig. 1. 
A small specimen of this species occurs in the collection. It is a broken specimen, 
with short and thick, obtuse lobes; the surface is roughened by irregular, low, somewhat 
sinuous, obsolescent ridges, between which the cells are placed either singly or in groups. 
The cells are generally very shallow and indistinct ; and the septa are from ten to twenty 
in number, uniformly very thin and finely granular, often very small, and united with 
each other. The surface between the cells is of very open and porous texture, having 
the form of oval or elongated, rectangular, interseptal areas, arranged somewhat as in a 
spider’s web, an arrangement apparently due to an abundant and regular development 
of synapticulee. 
Locality.—Amboina. 
2. Psammocora obtusangula (Lamarck). 
Pavonia obtusangula, Lamarck, Hist. Anim. sans Vert., ii. p. 240, 1816. 
Psammocora obtusangula, Dana, Zoophytes, p. 345. 
A large, broken specimen was obtained, which is in all respects typical of the species. 
Locality.—Tongatabu. 
3. Psammocora ramosa, n. sp. (Pl. VI. figs. 6-60). 
Corallum consisting of a cluster of numerous, rather thick, elongated, uneven, 
and somewhat contorted branches which spring from a thick, basal stock; the 
branches are subterete, much and rather closely divided, not coalescent, from 8 to 
12 mm. thick; continued above into short, irregular, compressed, clavate, or palmate 
branchlets, the terminal divisions being rather thick and obtuse, and often terete ; 
the corallum throughout is somewhat irregularly swollen or nodose owing to unequal 
rudimentary branches and branchlets. Calicles very small, 0°75 mm. wide, rather distant, 
superficial, with a minute depression at the centre, in which a very minute tuberculate 
