A MONOGRAPH OF THE EXISTING CRINOIDS 609 



beyond the IBr series are 4 (3 + 4). An external IIIBr series is missing. The cen- 

 trodorsal is small, with the dorsal pole 1.5 mm. in diameter. The cirri are XII, 15, 

 9 mm. long, somewhat compressed distally. 



Another specimen has 28 arms, of which the anterior are 120 mm. and the pos- 

 terior are 55 mm. in length. The anterior arms are excessively attenuated. The 

 cirri are XII, 12-13, very small and weak, from 6 to 7 mm. long. 



A third example has 28 arms, the anterior 90 mm. and the posterior 55 mm. long. 

 Of the IIBr series, 9 are 2 and 1 is 4 (3 + 4). All of the IIIBr series are 4 (3 + 4). 

 The cirri are X, with some rudimentary ones in addition, from 8 to 9 mm. long, and 

 distally compressed. 



A fourth specimen has 22 arms, of which the anterior are very attenuated and 

 reach 130 mm. in length. Of the IIBr series, 5 are 2 and 5 are 4 (3 + 4). The IIIBr 

 series are 4 (3 + 4). Although the arms are much longer, the calyx is the same size 

 as that of the preceding specimen. The cirri are X, 12, 8 mm. long, slender, and 

 arranged in interradial pairs. 



Of the remaining specimens, 3 have exactly 40 arms, all of the IIIBr series being 

 present; 4 others have 37, 33, 32, and 25 arms, respectively, 5 are small, and 1 is an 

 11 -armed young. 



The example from Siboga station 43 has 40 arms which are about 100 mm. long. 

 The IIBr and IIIBr series are all 4 (3 + 4). The centrodorsal is pentagonal, sunken 

 nearly to the level of the dorsal surface of the radial pentagon, with a few obsolete 

 cirrus sockets on the margin. 



The specimen from Siboga station 50 has 39 arms 120 mm. in length. The 

 IIBr and IIIBr series are all 4 (3 + 4). The centrodorsal is pentagonal, very slightly 

 raised above the surface of the radials. A single slender cirrus, 10 mm. long with 

 14 segments, remains. 



Miiller described Alecto timorensis as foUows : 



The centrodorsal is very small, slightly over 2.25 mm. in diameter. 



The cirri are XVI, 14. A few of the segments toward the base are longer than 

 the others, and their ends are thicker. 



The IIBr and IIIBr series are 4 (3 + 4). 



The arms are 36-40 in number, 108 mm. long. The distal intersyzygial interval 

 is usually 4 muscular articulations. 



The first pinnule, preceding the first brachial axillary, is three times as long as 

 the second of the same side. From that point on the pinnules are moderately equal. 



I examined Miiller's types in the Leyden Museum. The cirri are VI, XIII, 

 and XIV, 13-14. These specimens can be exactly matched with others which I 

 have studied from the Philippine Islands. 



The 2 specimens from Timor collected by the Gazelle each have about 40 arms 

 80 mm. long. One has one, the other 2, of the IIBr series 2 instead of 4 (3+4). 

 In both, all the remaining division series are 4 (3 + 4). 



The example from Siboga station 213 has 40 arms 80 mm. long. One IVBr 

 series is present, and one IIIBr series is lacking. All of the division series beyond the 

 IBr series are 4 (3 + 4). There are V cirri, and in addition several small stumps. 



The specimen from Siboga station 273 has 36 arms 100 mm. long. There are 

 II small cirri and several stumps. 

 9729831 40 



