REPORT ON THE ASTEROIDEA. 341 
Torres Strait as belonging to this species. The major radius measures 13 mm., and the 
form is far too small to permit of a definite expression of opinion as to the species. The 
example is figured on Plate LVI. to show the strikingly Pentagonastrid character of its 
abactinal plating at this stage of growth. 
Genus Hippasteria, Gray. 
Hippasteria, Gray, Ann. and Mag. Nat. Hist., vol. vi. p. 279. 
Goniaster (pars), Agassiz, Mém. Soc. Sci. Nat. Neuchatel, 1835, t. i. p. 191. 
Astrogonium (pars), Miller and Troschel, System der Asteriden, 1842, p. 52. 
This well-marked genus is represented by only a single species. Several authors have 
sought to establish distinct species on the basis of what appeared to be well-marked forms, 
but up to the present time none of these have stood the test when compared with a good 
series of examples. The genus as at present known is confined to the northern area of 
the Atlantic. 
Chorology of the Genus Hippasteria. 
a, Geographical distribution -— 
ATLantic: One species between the parallels of 40° and 80° (?) N. 
Hippasteria plana,—on the eastern side : off the British Islands, 
Bohusliin, Finmark, Lofoten, and off the Murman coast (fide Daniels- 
sén and Koren). On the western side: off Cape Cod, Nova Scotia, 
and northward (Verrill). 
8. Bathymetrical range: 30 to 150 fathoms. 
y. Nature of the Sea-bottom: Only stated in a few instances ; those recorded are Clay, 
Gravel, and Stones. 
Chorological Synopsis of the Species. 
| | Ocean. Range in Fathoms. Nature of the Sea-bottom. 
Hippasteria plana : A | Atlantic. 30 to 150. Clay, gravel, stones. 
1. Hippasteria plana (Linck), Gray. 
Pentaceros planus, Linck, 1733, De Stellis marinis, p. 21, tab. xii. No. 21; tab. xxxiii, No, 53. 
Asterias equestris (pars), Linné, 1766, Systema Nature, ed. xii., p. 1100. 
Asterias phrygiana, Parelius, 1768, K. Norske Vidensk. Selskabs Skrifter, vol. iv. p. 425, tab. xiv. 
figs. 1 and 2. 1 
