REPORT ON THE REEF-CORALS. 125 
Genus 2. Z'rochoseris, Milne-Edwards and Haime. 
Trochoseris, Milne-Edwards and Haime, Cor., iii. p. 57. 
or Duncan, Rev. Madrep, p. 147. 
The recent forms of this genus are closely similar to the young specimens of the 
genus Leptoseris, at the stage in which there is only a single central calicle. The two 
genera would seem to be distinguished simply by the nature of the scanty columella, 
which in Trochoseris is papillose and trabeculate, and in Leptoseris is tuberculate. 
Trochoseris stokest, Milne-Edwards and Haime. 
Haloseris crispa, Rousseau (non Ehrenberg), Voy. au pole sud de Dumont d’Urville, Zool., vol. v. 
pl. xxix. fig. 3. 
Trochoseris stokes, Milne-Edwards and Haime, Cor., iii. p. 58. 
A portion of a corallum was obtained which, from its general structure, and from 
the absence of radial calicles, seems to be referable to this species. The piece does not 
show the ealicular fossa, and apparently would form about one-third of the complete 
specimen. In the absence of the characters of the columella it may perhaps be doubted 
whether the fragment was not broken from a young specimen of a Leptoseris in which 
the radial calicles had not yet developed. 
Locality.—Tahiti, from 30 to 70 fathoms. 
Genus 3. Pachyseris, Milne-Edwards and Haime. 
Pachyseris, Milne-Edwards and Haime, Cor., ii. p. 89. 
oe Dunean, Rev. Madrep., p. 162. 
Professor Verrill’ considers that the name Undaria should be substituted for 
Pachyseris ; but, as used by Oken, Undaria is a synonym of Agaricia and cannot there- 
fore be adopted for another genus. 
Pachyseris speciosa (Dana). 
Agaricia speciosa, Dana, Zoophytes, p. 337, pl. xxi. fig. 7. 
Two fragments were obtained which are referable to this species. The ridges are 
often irregular, rounded, and very slightly elevated. The columella is absent or quite 
rudimentary.” 
The species is very close to Pachyseris levicollis, but is quite different from Pachy- 
seris speciosa, Milne-Edwards and Haime, which is evidently a new species, easily 
distinguished by its very acute and elevated ridges, which throughout the corallum are 
concave on their sides and very sharp at their margin, and by the abundant columella, 
2 Dana, Coral and Coral Islands, p. 336. 2 See Dana’s figure. 
