PART 5 A MONOGRAPH OF THE EXISTING CRESTOID3 335 



in regular or fairly regular columns. The dorsal pole is rounded and rough in two of the 

 specimens, sunken in the third. 



The cirri are LXIX-LXXVII, 23-32, usually 27-32. The cirri are long and strong, 

 much longer in proportion to the length of the animal than in the types of F. mawsoni, 

 particularly so in the largest specimen. The first two segments are short, the third is 

 about as long as broad. The fourth is twice as long as broad and distinctly waisted. 

 The fifth to about the ninth are about two and a half times as long as broad and faintly 

 waisted. Beyond the ninth the segments gradually decrease in length though all are 

 longer than broad. The distal segments possess a strong dorsal spine, the apex of which 

 is subterminal. The opposing spine and the terminal claw are strong. 



In the specimen with arms 95 mm. long, the basal rays are visible externally as 

 small triangular plates. In the other two specimens, the largest and the smallest, 

 only four basal rays are visible. 



The radials are short, especially in the midline, because their distal edges are 

 strongly concave. They are hi apposition for the greater part of their length but the 

 distal corners are free. The distal edge may be smooth or raised into a low, finely 

 thorny ridge. The IBr : are longer than the radials, not in apposition laterally. The 

 distal edge of each is raised on either side of the incision by the axillary into a thorny 

 Up at right angles to the surface of the ossicle. The axillary is rhombic, wider than the 

 IBr! with which it forms a prominent syuarthrial tubercle; its distal egde is smooth but 

 there are small spines on the free outer portions of its proximal edges. The inner edges 

 of the first brachials are much shorter than the outer; they do not meet, or at most 

 their corners meet, above the axillary; the distal edges are smooth or finely thorny. 

 The second brachial forms a slight tubercle where it incises the first; there may be fine 

 spines along part of its proximal edge but its distal edge is smooth. 



The first syzygy normally occurs between brachials 3+4 but in one specimen it 

 is between brachials 4 + 5 on one arm and 10 + 11 on another. The second syzygy is 

 usually between brachials 9 + 10 but it also occurs between 8 + 9 and 10 + 11. Syzygies 

 are numerous beyond the second with one to four brachials between the pairs. 



The brachials between the first and third syzygial pah's are nearly rectangular, 

 wider than long; those beyond are at first wedge-shaped and then triangular, a little 

 broader than long; farther out on the arm they become rectangular, at first broader 

 than long, then as long as broad. 



In the two large specimens the distal edges of the brachials between the first and 

 second syzygies are smooth. The first one to three of these brachials are smooth in 

 the small specimen but the others are raised distally, hi the midline only, into a group 

 of spines much smaller and lower than those of the types of F. mawsoni but, like them, 

 standing out at right angles to the arm. The distal edges of the brachials beyond the 

 third syzygy are the same hi all three specimens: they are produced into a row of strong 

 forwardly directed spines. 



The oral pinnules are longer and composed of a greater number of segments than 

 in the types of F. mawsoni and the first genital pinnule is farther out on the arm. P[ 

 is of 44 to 50 segments and 16 mm. long; P 2 of 38 to 45 segments, 15 to 16 mm. long; 

 P 3 of 35 to 43 segments, about 13 mm. None of the segments of the oral pinnules is 

 much longer than broad; the proximal have spiny dorsal carinations which become 

 reduced to low rounded protuberances on the segments at the tip of the pinnule. The 

 first genital pinnule is P 4 or more often P 5 . P 5 is of about 23 segments and 1 1 mm. long ; 



