A MONOGRAPH OF THE EXISTING CRINOID8 487 



but it is usually considerably smaller both in length and in stoutness, while P is always 

 much smaller than P d . The disk is 12 mm. in diameter and is naked and more or 

 less incised. Sacculi are abundant along the sides of the pinnule ambulacra. The 

 color in alcohol is dorsally brownish white, with the perisome the same or greenish 

 gray. 



Carpenter said that the three individuals upon which he based his Antedon 

 occulta are somewhat variable in their characters but apparently belong to the same 

 specific type. They were taken in the same dredge haul as the type specimen of 

 Antedon similis. They all agree in the presence of one or more IVBr series, in the 

 great development of the centrodorsal, which partially covers the axillaries, and in the 

 absence of the sharp straight edges to the elements of the IIBr and IIIBr series on 

 the outer sides of the postradial series which are so marked in similis. Carpenter 

 remarked that they are therefore pretty clearly distinguished both from similis and 

 from its close ally brevicuneata. But they vary considerably in the characters of their 

 lower pinnules. Those on the outer sides of each group of arms arising from a IIBr 

 axillary, and more especially on the outer side of the outermost arms of each post- 

 radial series, are generally rather longer and stouter than the corresponding pinnules 

 on the inner arms. But Carpenter was unable to make out any great constancy in 

 this arrangement, and it is much more marked in one of the two specimens with the 

 lower pinnules exposed than it is in the other. P 3 is generally much smaller than P 2 , 

 though sometimes nearly or quite equal to it in size, a character that may occur on 

 the inner as well as on the outer arms. In the individual that shows the greater in- 

 equality of the pinnules on the inner and outer arms they are generally stiff er and more 

 styliform than in the more regular example. The latter, according to Carpenter, thus 

 presents an approach toward conjungens, while the former rather resembles Antedon 

 protecta. These two species, however, have much less closely approximated post- 

 radial series and a smaller centrodorsal, which leaves the IBr[ visible as well as the 

 axillaries. I examined these three specimens at the British Museum in 1910. 



Two specimens from the Tonga Islands in the Hamburg Museum were described 

 by Dr. Clemens Hartlaub in 1890 as a new species, Antedon lepida, in the following 

 terms: The centrodorsal is convex. The cirri are about XVIII, 20-25, 12 mm. long. 

 The distal cirrus segments are spiny. The radials are partially visible. The IBr, 

 are short and are free laterally. The IBr 2 (axillaries) are short. IIIBr series are 

 present only on the outer side of the IIBr axillaries. There are no IVBr series. Each 

 postradial series bears six arms. The postradial series are only slightly separated. 

 The 30 arms are 40 mm. long, and have a smooth dorsal surface. The brachials are 

 triangular, later becoming bluntly wedge-shaped. The second syzygy is at about 

 the fifteenth brachial, and the distal intersyzygial interval is six or seven muscular 

 articulations. The lower pinnules are very slender. P, is 4 mm. long. P 2 is 9 mm. 

 long and is composed of about 20 segments, of which the outer are somewhat elongated. 

 P 3 is approximately of the same length, though a little smaller. P< is markedly smaller. 

 P 6 and P 8 are 3 mm. long. The succeeding pinnules then increase in length, reaching 

 5 mm. The disk is 10 mm. in diameter and is deeply incised. 



Hartlaub said that this species is distinguished by its very delicate structure and 

 by the fact that P 3 is almost as long as P 2 . Additional characters are the spines on 



