ANNOTATED LIST. 133 
ity, but this is probably quoted from Lyman (1882) ‘‘ Lower California: 22 fms.,” and Mr. 
Lyman means the lower or southern part of the State of California, as his material was 
from 5 miles south of Santa Barbara. I can find no record for Lower California proper. 
McClendon’s largest specimen was 11 mm. across the disk. In his description he says 
the disk is covered with “‘short, cylindrical stumps,’”’ but the nearly spherical granules 
hardly warrant that description, even when highly magnified. 
There is an interesting possibility that O. antipodum and papillosa do not represent 
a natural genus, but that the former is a specialized form derived from a southern Ophio- 
coma, perhaps erinaceus, while papillosa is derived from e@thiops. If this were to be the 
case, the remarkable geographical distribution of Ophiopteris would be explained, and we 
should have an extraordinary case of convergent evolution. <A careful study of the growth- 
stages in the two species of Ophiopteris would probably reveal the truth. 
OPHIOMASTIX. 
Miller and Troschel. 1842. Sys. Ast., pp. 84 and 107. 
Although so closely allied to Ophiocoma that a perfectly sharp line can not be drawn 
between the two groups, this genus is remarkable for the distinctness of its component 
species and for the constancy of color as a specific character. Typical species of Ophio- 
mastix are easily distinguished from typical Ophiocomas by the absence of granules and 
the presence of spinelets on the disk, and by the possession of conspicuous claviform arm- 
spines. But unfortunately there are several species of the genus which have a coating of 
disk-granules, and while low, conical spinelets are also present, some individuals of mixta, 
elegans, and asperula are not easily separated from the pumila group of Ophiocoma by the 
character of the disk-covering alone. Actual comparison of specimens makes the distinc- 
tion evident enough, but it is difficult to put it into words. On the other hand, claviform 
arm-spines are often wanting, especially in young individuals of Ophiomastix, while they 
are conspicuous in typical Ophiocoma wendtii and may occur in other species of that genus. 
It is a remarkable fact that each of the 13 species of Ophiomastix described since the 
genus, based on a single species, was named in 1842, seems to be valid, and there are no 
synonyms to be assigned to any one of the species, except the most peculiar flaccida, which 
was first described by Lyman in 1874, and in 1878 was redescribed by Smith as a new 
species, type of a new subgenus. Smith recognized the close relationship of his specimen 
to Lyman’s, but thought certain differences warranted their separation. These differences 
were due, however, to condition of the specimens and are not at all constant. Neverthe- 
less, flaccida is an aberrant Ophiomastix, and Smith’s suggestion of a new subgenus for it 
is a very natural one, if subgenera are to be recognized. In no other case has a writer 
described a species of Ophiomastix which does not seem to be valid, but, as already pointed 
out (p. 122), the form which Brock (1888) called Ophiomastix pusilla is better treated as 
an Ophiocoma. 
One reason why there are not more misidentifications of the species of Ophiomastix 
is undoubtedly found in the fact that the pattern of coloration is very constant in each 
species of the genus, and even the shades of color show relatively little diversity. This is 
so different from the condition found in Ophiocoma that it furnishes a very striking proof 
of the fact that the value of color and color-pattern as taxonomic characters can only be 
determined by actual study of the genus or species concerned and can not safely be assumed 
on any @ priori ground. 
The growth changes in Ophiomastiz are as yet but little known. The few very small 
specimens at hand suggest that the specific characters are assumed rather slowly. Indi- 
viduals under 10 mm. disk-diameter have the upper and under arm-plates longer than 
wide and very different in shape from that found in adults of the same species. The adoral 
plates and oral shields are also very different from the adults in very young specimens, 
