A MONOGRAPH OF THE EXISTING CRINOIDS 529 



Description. The centrodorsal is a moderately thick disk, with a flat or some- 

 times slightly concave dorsal pole. The cirri are arranged in one or several irregular 

 marginal rows. 



The cirri are XX-XXX, 20-25, about 16 mm. long. The majority of the seg- 

 ments are longer than broad. The outer part of the cirri is a little compressed laterally. 

 The segments in the outer half of the cirri bear blunt dorsal spines. 



The radials are visible in the interradial angles. The IBr! are short and broad 

 and arc often only slightly united laterally. The IBr 2 (axillaries) are short, broadly 

 pentagonal or almost triangular. The postradial series divide three times. The IIBr 

 and IIIBr series are 2. The IIIBr series arise as a rule only on the outer side of the 

 IIBr axillaries. Slight synarthrial tubercles are present. There are either no, or 

 only very slight, protuberances on the outer sides of the postradial series. 



There are not more than 31 arms, which are 110 mm. long. The arms have a 

 smooth dorsal surface and are very slender. The second brachials are a little longer 

 than the first. The first syzygial pair (composed of brachials 3+4) is approximately 

 squarish but a little broader than long. This is followed by a few short discoidal 

 brachials, which are succeeded by moderately short almost triangular brachials, of 

 which from 12 to 14, though sometimes more, may be present. The following brachials 

 are more bluntly wedge-shaped, finally becoming more oblong. 



The first syzygy is between brachials 3+4, and the second is from between bra- 

 chials 9+ 10 to between brachials 16+17. The succeeding syzygies occur at intervals 

 of two to four muscular articulations, sometimes also in groups of two. 



The pinnules of the first pair are very delicate and small and taper rapidly after 

 the three or four first basal segments, which are broadened. The pinnules of the 

 following pair (P 2 and P b ) are markedly larger and measure about 9 mm. They are 

 moderately slender and are composed of about 20-25 segments, which may be a little 

 longer than broad. The pinnules of the third pair (P 3 and P c ) are as a rule likewise 

 markedly longer than those of the first pair (Pi and P a ), although only three-fourths 

 as long as P 2 and P b . The pinnules of the three following pairs are considerably 

 smaller. The length of the succeeding pinnules increases and reaches about 9 mm. 

 The basal segments, especially the third and fourth of the four lowest pinnules, are 

 moderately broad and often a little carinate. 



The disk is 15 mm. in diameter and is strongly incised. There are fine calcareous 

 rods in the marginal lappets and tentacles of the pinnules. Sacculi are thickly placed 

 on the pinnules. The color is a uniform dark blackish brown. 



The preceding description is adapted from Hartlaub's account of five specimens 

 in the Berlin Museum from the Red Sea collected by Hemprich and Ehrenberg. One 

 of these was later transferred to the Gottingen Museum. 



Notes. In one of the specimens from Suez Bay the dorsal surface of the centro- 

 dorsal is simply flattened. There are 27 arms. The second syzygy occurs from be- 

 tween brachials 18+19 to between brachials 20 + 21, and the distal intersyzygial 

 interval is 9 or 10 muscular articulations. Another specimen from Suez Bay is 

 uniform purplish black. 



Mortensen said that one of the specimens from Port Taufiq is very young, and 

 the specimen from the Gulf of Suez (station R. 6) is in very poor condition; the identi- 

 fication of these two specimens, therefore, is not beyond doubt. H. Munro Fox said 



