22 
PACIFIC SCIENCE, Vol. IV, January, 1950 
The special dermal spicules are usually 
regarded as tylotes, but the ends are so min- 
utely enlarged that the spicule at first seems 
to be a strongyle and often really is a stron- 
gyle. It is rather that there is a very slight 
constriction near the end of each spicule than 
that the end is actually swollen. On each 
extreme tip of these spicules there are a num- 
ber of very fine spines. These spicules nearly 
all range in size between 3 by 180 and 4 by 
210 g. The principal spicules are smooth 
styles, often curved a little, and range from 
6 by 160 to 8 by 210 g. The abundant 
microscleres are peculiar microspined raph- 
ides, usually less than 1 g in diameter, but 
occasionally as thick as 2 g with total lengths 
up to at least 200 g. 
Within the genus Tedania there are some 
45 names, besides others that have been trans- 
ferred to other genera. Some of the 45 are 
clearly synonyms, but others arouse serious 
questioning. There are some well-marked 
differences. One group of three or four spe- 
cies has two distinct categories of micro- 
scleres. On the west coast of North America 
two species (or is it all one?) have tylostyies 
instead of styles for principal spicules. Some 
deep-water species have enormous spicules 
and distinctive, symmetrical habitus. There 
remain about 20 species that differ in color 
and in having spicules a little larger 
or smaller. Burton (1932: 344) and ^Iso 
Burton and Rao (1932: 353 and following) 
argue that all these are conspecific and call 
them all Tedania nigrescens , which then 
would become an amazingly cosmopolitan 
species. Perhaps some further analysis is in 
order, and, in particular, color may be quite 
significant. 
The genus Tedania was established by 
Gray (1867: 52) for Reniera digitala 
Schmidt (1862: 75) and Reniera ambigua 
Schmidt ( 1864: 39). The former was shown 
to be a synonym of Reniera nigrescens 
Schmidt ( 1862: 74) and the type is assumed 
by Burton and others to be called nigrescens . 
This designation was made official by de 
Laubenfels (1936: 89). Topsent (1939: 5) 
pointed out, however, that digitata and nigre- 
scens both fall to the earlier Halichondria 
anhelans Lieberkiihn (1859: 522). This 
species, under various names, is well known 
from the Mediterranean, where it seems to 
be the only Tedania. It is regularly and con- 
sistently described by the various authors as 
being black or nearly so; some say very dark 
blue, some say very dark green. I have not 
found these colors in the field or in the lit- 
erature from other parts of the world. It may 
be that the Mediterranean form is well char- 
acterized by color. Burton and Rao have 
implied, but without actual data, that it has 
similar spiculation to West Indian Tedania. 
On the other hand, published descriptions 
show that the Mediterranean Tedania has the 
endosomal styles two to seven times as thick 
as the ectosomal tornotes. I find, in very 
numerous specimens, no such difference in 
West Indian Tedania, in which the thickness 
varies from the same to one and one-half 
times that of the tornotes. 
The West Indian form, which I am con- 
vinced is specifically distinct from anhelans, 
was first named Thalysias ignis by Duchas- 
saing and Michelotti (1864: 83) and trans- 
ferred to Tedania by Verrill ( 1907 : 339) • It: 
is regularly brilliant red, almost spectral red, 
but tending a little toward vermilion. I have 
examined thousands of specimens, and found 
extreme uniformity. 
Numerous species names for Tedania have 
been established for forms occurring in the 
East Indian region. These all have spicules 
thicker than those of ignis; they vary from 
slightly longer to one and one-half times as 
long. The colors are usually cited as yellow, 
in a few cases tending toward red. 
The allocation of the Hawaiian Tedania 
must be regarded as provisional; I do not 
feel that its position can be settled at present. 
If the attitude of Burton and Rao is adopted, 
it is Tedania anhelans, and so are a score of 
