igo DISCOVERY REPORTS 



or at most their corners meet, above the axillary ; the distal edges are smooth or finely 

 thorny. The second brachial forms a slight shoulder 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 the third and fourth brachials but in one 

 specimen it is between the fourth and fifth brachials on one arm, between the tenth and 

 eleventh on another. The second syzygy is usually between the ninth and tenth 

 brachials but it also occurs between the eighth and ninth and the tenth and eleventh. 

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



The brachials between the first and third syzygial pairs 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 speci- 

 men but the others are raised distally, in the mid-line only, into a group of spines much 

 smaller and lower than those 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 in 

 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 

 F. mawsoni and the first genital pinnule is farther out on the arm. Pi is of 44-50 seg- 

 ments, 16 mm. long (Fig. 4 c) ; P2 of 38-45 segments, 15-16 mm. ; Pg of 35-43 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 pro- 

 tuberances on the segments at the tip of the pinnule. The first genital pinnule is P4 or, 

 more often, P5. P5 is of about 23 segments and 11 mm. long; the gonad lies along 

 the fourth to the tenth or eleventh segments. The other genital pinnules are of between 

 23 and 30 segments and up to 16 mm. long; the gonads usually lie along the third to 

 eighth segments. All but the first two segments of the genital pinnules are considerably 

 longer than broad. Their distal edges are beset with fine spines. 



The disk is naked. Sacculi are abundant. None of the specimens shows any trace of 

 an ambulacral skeleton. In the largest specimen there are many spicules, some smooth 

 and rod-like and others branched, in the tentacles of the distal segments of the outer 

 pinnules (Fig. 4 d). 



The specimens are of a pale straw colour in spirit, darker on the pinnules than else- 

 where. There is a yellowish tinge on the distal parts of the cirri and pale brown spots on 

 the gonads and the tissues on the inner sides of the arms. Some of the brachials have 

 a bluish tinge along the sides. 



One of the specimens has a large cyst of Myzostomiim cysticoliim v. Graff lying be- 

 tween the bases of a pair of its arms with its lower extremity resting on the disk. 



Florometra antarctica is distinguished from F. mawsoni by its considerably longer 

 oral and genital pinnules which are composed of a greater number of segments. The 



