PAKT 5 A MONOGRAPH OF THE EXISTING CRESTOIDS 273 



type, though the latter have the same smooth elongated character in both. 



Although of larger size, more of the radials are visible, while the axillaries have 

 sharper proximal angles and the IBr : are therefore more incised. 



There are slight indications of lateral flattening upon the 4 lower brachials. 



The segments of PI are relatively longer than in the type. 



Notes. Thanks to the courtesy of Prof. F. Jeffrey Bell, I was able to examine both 

 these specimens in the British Museum. After a study of the larger example I decided 

 that this form is closely related to Th. tenelloides, but it is a smaller species with longer 

 brachials which are not so nearly oblong. There is the same short segmented P t ; P 2 

 and P 3 are large and stiffened; P 2 is slightly larger and longer than P 3 ; P 4 is smaller 

 than P 2 and P 3 . 



In the smaller individual there are 15 cirrus segments of which the proximal are 

 very long. P t is short with comparatively few long segments; P 2 and P 3 are large. 



This last is the specimen figured by Carpenter under the name notata; but his notes 

 on notata evidently refer to the individual figured as tenuicirra, except in regard to the 

 number of the cirri, the incision of the IBri, and the character of PI. [NOTE BY A.M.C.] 

 The type specimen of notata is not now (1958) to be found in the British Museum. The 

 type of tenuicirra is in very poor condition, the centrodorsal broken and the radials 

 separated. The cirri are detached but a few remain in the jar. One with 16 segments 

 has the third segment already over twice as long as broad and the fourth and fifth are 

 about six tunes as long as broad. No complete PI remains but the basal six or seven 

 segments are about as long as broad. P 2 has 14 segments and is 5 mm. long. Only the 

 first two segments are not longer than broad. 



Some further specimens of this species were obtained by the Danish Expedition to 

 the Kei Islands hi 1922, about which nothing has been published. Since they show 

 some differences from the types, a full description is given here. 



The centrodorsal is rather sharply conical, nearly twice as broad basally as it is 

 high, with the sides almost completely covered with closely crowded cirrus sockets 

 which decrease slowly hi size towards the apex. 



The cirri are XL, 22-24, 25-30 mm. hi length. They are very slender, nearly 

 straight, tapering gradually from the base to an attenuate and very pointed tip. The 

 first segment is very short, three tunes as broad as long, the second is half again as 

 broad as long, the third is usually slightly longer than broad but may be slightly broader 

 than long, the fourth is from two to three tunes as long as broad, and those following are 

 much elongated, in the central portion of the cirri being five or six times as long as the 

 median width with slightly swollen ends and distally about four times as long as broad 

 with the dorsal and ventral profiles nearly straight. The antepenultimate and penul- 

 timate segments are perfectly straight and taper gradually, the latter being exceedingly 

 slender and ending almost hi a point, which bears the extremely small conical terminal 

 claw. 



The distal portion of the radials is visible as a very narrow band beyond the rim 

 of the centrodorsal. The IBr! are nearly or quite four times as broad as long hi the 

 median line, somewhat incised in the median line by a proximal process from the 

 axillary. The lateral borders are hi contact basally. The IBr 2 (axillaries) are about half 

 again as broad as long. The distal sides are slightly curved and are at right angles to 

 each other. The distal apex is slightly produced. There is a slight, well-rounded 

 proximal median projection. 



