OF THE LEYDEN MUSEUM. 185 
exteriorly) are present. The synarthrial tubercles are slightly 
prominent, and the basal portion of the arms is rugose as 
in LD). protectus. The division series are not in lateral con- 
tact, though they have tolerably straight sides; the IBr, 
are entirely united laterally, but the axillaries are free. 
There are no lateral processes such as are seen in Stepha- 
nometra. P, has from twenty to twenty-two segments; P, 
is small and weak; P, is nearly twice as long as P,, and 
P, is still longer; P, is nearly as large as P,, being in- 
termediate between P, and P,; P, is much shorter; the 
following pinnules are small and weak. The proximal 
pinnules resemble those of the preceding specimen, but 
are slightly less stiffened, and are more flexible and more 
flagellate distally. 
There appear to be no differences between these two 
specimens not to be accounted for by the difference in the 
size of the two individuals, and there can be little doubt 
but that they in reality belong to the same species. 
Dichrometra bimaculata (P. H. Carpenter). 
Antedon bimaculata 1881. P. H. Carpenter, Notes from 
the Leyden Museum, vol. 3, p. 186. 
Dichrometra bimaculata 1909. A. H. Crark, Proc. Biol. 
Soc. Washington, vol. 22, p. 138. 
Amboina (coll. Ludeking). — This is a very cha- 
racteristic species and was well described by Carpenter; 
P, is twice as long as P,; P, is considerably longer and 
stouter than P,; P, is about the length of P,, but has 
slightly shorter segments; P, is considerably shorter, with 
only thirteen segments, but of the same character as the 
preceding. The lower pinnules are stiffened about as is 
P, in D. protectus; they are not especially enlarged, and 
are perfectly smooth, not being basally carinate; P, is 
quite appreciably larger and longer than either P, or P,, 
there being considerably more difference than in the case 
of D. flagellata. The centrodorsal is large, thick discoidal, 
Notes from the Leyden Museum, Vol. X XXIII. 
