A MONOGRAPH OF THE EXISTING CRINOIDS 663 



considerably in timorensis, and very greatly in parvicirra. In these features the latter 

 also intergrades with samoana. 



The curious specimen of parvicirra from Cape Baudin, with the elements of the 

 division series bluntly carinate and with swollen edges, has no counterpart in any of 

 the other species of Comasteridae. 



The division series in both timorensis and parvicirra are highly variable in the 

 relative proportion of series of 4 (3+4) and of 2; but they are never, except as a 

 very rare abnormality, irregular. The IIBr series in both may be all 4 (3+4), or 

 they may be all 2, or the 2 types may occur together in any proportion. Generally 

 speaking, the IIBr 4 (3 + 4) series are in the majority. The same is true of the IIIBr 

 series. While individuals with a large number of IIIBr series all of which are 2 are 

 very rare, such have been recorded, and these approach closely certain of the more 

 generalized species of Comantheria. 



Thus Dr. H. L. Clark has described as callipeplum, which he said is nearly related 

 to Comantheria briareus, a specimen which, after examination, seems to me to be 

 nothing but an unusually fine example of timorensis. 



In timorensis the synarthrial articulations may always be identified as such, 

 but the closeness of the synarthrial unions in parvicirra varies very greatly, so that 

 certain individuals are easily mistaken for one or other of the small species of Comaster. 

 Indeed, I am not sure but that in parvicirra the proximal synarthries are not sometimes 

 more or less completely transformed into syzygies, and that therefore the main differ- 

 ential character between Comaster and Comanthus, which serves to distinguish at a 

 glance the larger species of these genera, is not subject to a certain amount of inter- 

 gradation hi the smaller forms. 



Carpenter called attention to the extraordinary variation in the combs on the 

 oral pinnules in 1879. In the series of specimens which he described as polymorpha 

 he said that the last 6 or 8 segments of the pinnules on the division series and the first 

 8 or 10 brachials have the outer ventral margin of each calcareous segment produced 

 into a small lancet-shaped process which bends over toward the ventral side, so that 

 the end of the pinnule has a comblike appearance. Many of the other pinnules until 

 near the end of the arm have similar processes upon their 4 or 5 terminal segments. 

 There is a possibility that this last observation may have been based upon an 

 unrecognized specimen of one of the small species of Comaster, but of this there is no 

 clear evidence. 



In variety 1 of polymorpha from Ubay combs occur regularly as far as the sixth 

 brachial pinnule, and thence at intervals to about the twentieth brachial, but no 

 further. The cirri as described for this variety are very unusual for parvicirra, and 

 it would seem as if the specimen might have been an example of Comaster tenella; 

 but the distribution of the syzygies does not support this view. 



In variety 2 from Cabulaun the comb is limited to the pinnules of the division 

 series and the first 5 brachial pinnules. 



In variety 3 from Bohol (timorensis) the comb occurs on the pinnules of the 

 division series, on P 1; and occasionally on the pinnules of the fourth-sixth brachials, 

 but on no others. 



