278 AGALMA OKENI. 



as well as to that by Lens and Y&n Riemsdijk. The characters most readily 

 distinguishing A. okeni from other Agalmids are the short, non-contractile stem 

 and the thick, stiff, closely crowded bracts. Its general form and its habit 

 of floating horizontally in the water are so characteristic that it is recognizable 

 at first sight. The largest examples in the "Albatross" series measure about 

 95 mm. in length, while Dana's single example was about 60 mm. long. This 

 size, equalled by only one of the "Siboga" specimens, is apparently about the 

 maximum, for Chun's ('97a) largest specimen was only 75 mm., while Haeckel's 

 examples and those which I have examined from the West Indies were all much 

 smaller. 



Nedosome. The pneumatophore is invariably deeply pigmented apically. 

 The arrangement of the nectophores, which are closely crowded together in two 

 regular opposed rows, has been described and figured by Haeckel. In the 

 largest specimen there are about twenty-eight nectophores (excluding several 

 very young ones which had not attained their definitive form). Chun has 

 recorded twenty-four in his largest example (75 mm.). In examples 40-50 

 mm. long, there are usually 14-18 nectophores, and in tlie younger individuals 

 proportionately fewer. The exact number cannot be determined for any of 

 our small specimens, for all of them had lost most of their nectophores. Indeed 

 they were in all ways less satisfactory than the larger ones. The nectophores 

 themselves are of such a characteristically flattened and prismatic form (Plate 17, 

 fig. 12) that they are readily recognizable even when detached. And the course 

 of their subumbral canals agrees perfectly well with Haeckel's figure ('69a, pi. 10, 

 fig. 67). The nectosac itself is prolonged laterally into two horns, a character- 

 istic form which is constant even in the most contracted specimens. The 

 largest nectophores measure 11-12 mm. in breadth. 



Siphosome. The largest number of siphons in any colony was nine, the 

 same number that Chun records for his largest examples; most of the speci- 

 mens (40-50 mm. long) had six or seven. The smallest number (except in some 

 mutilated fragments) was two, in a somewhat contracted colony 4 mm. long. 



Bracts. The bracts have been well described by Haeckel. They are 

 prismatic in outline, roughly triangular (Plate 17, fig. 10, 11), and thickest at 

 the distal end. The distal margin is divided into four concave facets by three 

 vertical transverse ridges in an extremely characteristic manner, and the number 

 of facets, which are very early developed (Plate 17, fig. 9), is apparently constant. 

 The only exception to it which I have seen among many hundred bracts is that 

 in very small specimens the bracts associated with the oldest (primary ?) siphon 



