RAYMOND: NEW FOSSIL STARFISH. 169 
For the sake of clarity it may be well to recapitulate briefly 
the generic characteristics of the present subdivisions of the 
Hudsonasteridae. 
Family Hudsonasteridae Sehuchert. 
Small asterids with large, thick plates, and no accessory ray- 
plates of any kind. Each interbrachial area occupied by a single 
large plate against which the infra-marginals abut, but which 
always forms a part of the outer row. Disk with a central 
plate surrounded by large plates arranged in regular cycles. 
Protopalaeaster Hudson. — Adambulacrals about twice as 
numerous as the infra-marginals; no podial excavations. Inter- 
brachial plate six-sided, wide and rounded exteriorly. Type, 
Protopalaeaster narrawayi Hudson, Black River, near Ottawa, 
Ontario. 
Macroporaster gen. nov. — Adambulacrals about one and 
one-half to two times as numerous as infra-marginals. Podial 
excavations large. Interbrachial six-sided, but more pointed 
at both ends than in Protopalaeaster. Type, Palaeaster matu- 
tinus Hall. Ordovician and Silurian, eastern North America. 
V HuDSONASTER Sturtz. — Oral side unknown. 
Girvanaster Spencer.^ — Ambulacrals about twice as numer- 
ous as infra-marginals, which are usually large. Interbrachials 
rhombic, almost diamond-shaped. Type, Girvanaster sculptus 
Spencer. Ordovician, Scotland. 
CocASTER Spencer. — -Adambulacrals about one and one-half 
times as numerous as infra-marginals. Interbrachials pentag- 
onal, pointed inwardly. Podial excavations small or absent. 
Type, Cocaster hulbiferus Spencer. Silurian, England. 
Belaster Spencer. — Adambulacrals but slightly more numer- 
ous than infra-marginals. Interbrachials long, narrow, ex- 
panding inward. Arms rather long and slender. Type, Belaster 
ordovicus Spencer. Ordovician, Scotland. 
SiLURASTER Jaekel. — Adambulacrals but slightly more nu- 
merous than infra-marginals. Podial openings small. Inter- 
^Palaeontographical Soc, London, vol. for 1915, 191G, p. 70. 
