A MONOGRAPH OF THE EXISTING CRINOIDS 189 



the second brachial has the form of an axillary to a marked degree, the first syzygy is 

 between brachials 5+6. 



PI is markedly longer and stouter than P 2 . In the larger specimen it is 5 or 6 mm. 

 long, stout basally, and composed of 10 segments of which the second, and especially 

 the third, are markedly broadened and those following taper rapidly. P 8 is about half 

 as long as PI with about 10 segments of which none are especially broadened, the width 

 of the segments tapering gradually from the base of the pinnule to the tip; the majority 

 of the segments are somewhat elongated. P 3 is very similar to P 2 in thickness and in 

 length, but the fourth and fifth segments sometimes show a thin leaflike expansion over 

 the gonads, which are here only slightly developed. P 4 is somewhat longer and shows 

 hi pronounced measure the thin leaflike expansion of the third, fourth, and fifth seg- 

 ments, the fourth being the most broadened. The following pinnules as far as P 8 are 

 similar, and all these show gonads on the ventral side. Whether the pinnules with 

 strongly developed expansion of the earlier segments extended farther out along the 

 arms could not be definitely ascertained. The pinnules of about the middle third 

 of the arm are all very small. 



The disk is not visible. The ambulacral plating of the pinnules consists of high 

 slide plates and covering plates. Sacculi are not recognizable. 



The color in alcohol is brownish white. 



Hartlaub remarked that this description differs in some points from the notes 

 published by Carpenter. Carpenter said that the cirri are "without definite arrange- 

 ment" whereas they are arranged in 10 definite columns; he also said "Radial axillaries 

 long," whereas apart from the proximally directed process in the middle of the proximal 

 border they are very short. 



The third rather small specimen that was found with others identified as A. 

 brevipinna agrees with the other two. The centrodorsal has five interradial and five 

 radial ridges. No cirri are present. As in the smaller of the two other specimens the 

 radials are visible and are very flat. The radials and the IBr series in this specimen 

 agree almost exactly with those of the smaller of the other two. The IIBr series are 2. 

 The form of the IIBr series and of the first two brachials, and especially of the first 

 syzygial pair, are approximately as in the larger of the two others. There are no 

 IIIBr series. There are 15 arms about 20 mm. long. The first syzygy is between 

 brachials 3 + 4 and the second is between brachials 17+18. 



PI is about 2 mm. long and is composed of 9-12 segments of which those in 

 the proximal portion are stout and those in the outer half more slender. The first 

 three segments are broader than long, those succeeding elongated, the terminal shorter 

 again. In general P 1 resembles the same pinnule in the two other specimens. Pj is 

 about half as long as PI with 5 or 6 segments of which the first-third are markedly 

 stouter than those following. The pinnules succeeding are of the same form and 

 length but are composed of fewer segments, as is the case with the corresponding 

 pinnules in the other specimens; there is the same leaflike expansion of the lower 

 segments. 



The disk is not visible; the color in alcohol is brownish white. 



Hartlaub pointed out that Horaeometra duplex is especially noteworthy on account 

 of its relatively small size, his largest specimen, with the arms only 45 mm. long, hav- 



