AGALMA OKENI. 279 



have only two distal facets, there being only one transverse ridge. The peri- 

 pheral glands discovered by Lens and Van Riemsdijk (:08, pi. 13, fig. 104) are 

 present in some bracts at least, but apparently not in all. 



The arrangement of the bracts on the stem is extremely precise and regular. 

 The firm and regular pavement-like cylinder of closely opposed bracts has 

 been aptly described by Haeckel ('88b) as a "carapace," but he is in error in 

 stating that the dorsal half of the axial trunk is "exclusively composed of bracts." 

 In reality the bracts are attached exclusively to the ventral half of the stem, 

 a fact easily demonstrated on well-preserved specimens. The bracts occupy 

 the space between the siphons as Haeckel supposed, for being ventral hke the 

 latter, they must necessarily alternate with them. Each bract is borne on a 

 semilunar muscular lamella, the youngest ones ventral, and nearest the siphons; 

 the older ones more dorsal, and nearer the centre of the "internodes" (Plate 17, 

 fig. 13). The broad axis of each bract lie transverse to the long axis of its mus- 

 cular lamella; and by the curving of the older lamellae the armor of bracts is 

 made even more complete on the dorsal than on the ventral side of the sipho- 

 some. Chun's statement ('88) that only the bracts nearest the siphons have 

 canals is only partly correct. In point of fact, every bract has a canal when 

 young, but as they grow older and are forced further and further dorsad, the 

 canals become less conspicuous, and in some cases cannot be detected at all. 

 The largest bracts which I could find are 15 mm. broad, and all are extremely 



hard and rigid. 



The succession of the siphons, palpons, and gonophores is regular and 



characteristic. If we take any well-preserved segment of the stem, we find in 

 each cormidium the siphon, several palpons, and the two gonodendra, 9 and cf . 

 The gonodendra lie immediately distal ' to the siphon, in conjunction with two 

 or three palpons; the 9 next to the siphon (Plate 17, fig. 13). Proximal to 

 each siphon is a cluster of several palpons. I have found no essential variation 

 from this arrangement in any of the cormidia studied, except that the shorten- 

 ing of the stem in contracted material may cause the gonodendra to lie nearly 

 midway between pairs of siphons. - But in expanded examples the true condi- 

 tion is easily traced, and in such there is a free space, occupied only by bracts, 

 between each two cormidia. Chun ('88, p. 1 170) it is true, says that "die mann- 

 lichen geschlects trauben proximal, die weiblichen distal angeordnet sind," 

 but he does not give any figures of this. The cf and 9 gonodendra differ so 



' I speak of the end of the siphosome nearest the nectosome as proximal, that furthest from it 

 (i. e., oldest) as distal. 



