312 ECHINODKRMA OF THE INDIAN MuSEUM, FART VII. 



externally an undivided arm ; all the first syzygies in the aims of this ray are 

 between the second and third brachials. The total number of arms on this raj' is 

 seven, arranged in 1, 2^ 1, 3 order. 



On the arms where the first syzygy is between the second and third brachials 

 the first brachials always bear pinnules : but on the arms where the first syzygy 

 is between the third and fourth brachials the first pinnule is on the second bra- 

 chial. 



In this specimen all but one of the llBr series are 2, while of the ten lIIBr 

 series present five are 2, three are 3 (2+3), one is i (3-(-4), and one 5 (4+5); 

 the six IVBr series are all 3 (2+3). In the thirty-six arms the first syzygy is 

 between the second and third brachials in twenty-nine, between the third and 

 fourth in six, and between the fifteenth and sixteenth in one. 



This specimen exhibits an unusual amount of I'eversional characters ; the 

 division series of 2 are the division series of Comatella. representing the so-called 

 compound type of arm division, and are not the primitive division series of two 

 ossicles as are found for instance in the genus Dichrometru. A large part of this 

 specimen therefore would be unhesitatingly referred to some species of Comatella 

 were it studied without regard to the remaining portions. The division series of 

 4 (3+4) is of the type characteristic of the subfamily Comasterins, and in 

 particular of the genus Comanthus ; it is the simplest type of arm division found 

 in the whole family. The division series of 5 (4+5) is a variant of no particular 

 significance. The syzygies between the second and third brachials are those of 

 the genus Capillafiter, and are normal for that genus only ; those between the 

 third and fourth brachials are normal for the species of the subfamily Comasterinae 

 only when occurring on the inner arms, but when found on the outer arms are 

 normal botii for the species of Comasterina' and for the species of Comatella : the 

 syzygy between the fifteenth and sixteenth brachials is a variant. 



Analyzed on the basis of the characters furnished by the division series and 

 the arms, we find this specimen to represent the genus Capillaster, the genus 

 GoTnatella and the subfamily Comasterina:' in the following proportions: — 



Arm Division. Arms. Total. 



Gapillaster SS°i, 75% 56-50/„ 



Oomatella 54 6 300 



Oomasterinpp 6 17 11"5 



(Variant) (2) (2) (2-0) 



100 luO 1000 



Xow the curious arm division of tlie species of the genus Capillanter beyond 

 the IlBr series is in reality exactly tlie same as that of the species of the subfamily 

 Gqmasterinas (and of all the endocyclic families in which the IIlBr series are 

 4 (3+4) except that the first component of the interpolated Z pair (the ossicle 

 corresponding to the first primitive brachial) is omitted in all the division series 



