REPORT ON THE ASTEROIDEA. 279 
acquainted, and is readily distinguished from all the Pacific forms at present known. Its 
general character points to some alliance with Pentagonaster intermedius, of which Penta- 
gonaster arcuatus is perhaps the Pacific representative. In some of its structural details 
Pentagonaster arcuatus resembles forms grouped in the genus Nymphaster, of which I 
was at first disposed to consider it an aberrant species. Iam still in some doubt as to 
whether this form is correctly referred to the genus Pentagonaster, but with only a single 
example for study, that course appeared to me the most justifiable. 
Genus Calliaster, Gray. 
Calliaster, Gray, Ann. and Mag. Nat. Hist., 1840, vol. vi. p. 280. 
This genus was established by Gray in 1840, but was merged by Perrier! in 1876 in 
the genus Pentagonaster, with doubtful subgeneric rank. A fine series of well-preserved 
specimens, comprising the types of Gray’s species, exist in the British Museum; and after 
a careful study of these, together with the new form, I consider that the genus established 
by Gray should be maintained. The characters of the adambulacral armature, of the 
actinal intermediate plates, and of the general facies of the form appear to me to be 
worthy of recognition, at least until more is known of the internal anatomy of the various 
members of the Pentagonasteride, and of the true taxonomic value of the correlated 
external structures. 
Chorology of the Genus Calliaster. 
a, Geographical distribution :— 
ATLANTIC: One species between the parallels of 30° and 40° S. 
Calliaster baccatus off the Cape of Good Hope. 
Paciric: One species between the parallels of 30° and 40° N. 
Calliaster childreni off the coast of Japan. 
8. Bathymetrical range: Appears to be confined to the Littoral zone: 18 fathoms is 
the greatest depth recorded by the Challenger. 
y. Nature of the Sea-bottom: Not recorded. 
Chorological Synopsis of the Species. 
Ocean. | Range in Fathoms, Nature of the Sea-bottom. 
Calliaster baccatus  . : ; Atlantic. | 5 to 18 
Calliaster childreni . .  . | Pacific. | ‘a 
‘ Révis. Stell. Mus., p. 215 (Archives de Zool. expér., 1876, t. v. p. 31). 
