280 J. H. ASHWORTH. 



which are at first simple, very soon show indentations or 

 pinnules. He regarded such individuals rather as young 

 polyps than as zooids. They were more numerous in the 

 outer part of the arclied end of the stem. In a new species, 

 Xenia fuscescens, Klunzinger described the small polyps as 

 very numerous, outnumbering the large polyps, and filling up 

 the intervals between the bases of the latter. He wrote that 

 these small individuals do not appear to develop into fully 

 f(jrmed polyps^ but to remain in the bud-like stage, with short, 

 simple, mostly incurled tentacles. They are 1 mm. to 2 mm. 

 long and "5 mm. broad, and are cylindrical or club-shaped. 

 On account of the large numbers of these small indivi- 

 duals, Klunzinger placed his Xenia fuscescens near the 

 Heteroxenia Elizabethse of Kolliker. There are no 

 transition stages between these small individuals which do not 

 appear to develop into larger polyps and the adult polyps, and 

 from the description and figures they appear to be quite as 

 distinct as the two kinds of individuals described by Kolliker 

 in Heteroxenia. 



Haacke (1887), who examined some of the Xeniidse in 

 Torres Straits, says that the small individuals are merely 

 young polyps, and all stages of development between them and 

 the adult polyps may be met with. Therefore he denies the 

 occurrence of heteromorphism in the Xeniidae. 



Wright and Studer in the 'Challenger Report' (1889) 

 record the observations of Klunzinger and Haacke noticed 

 above. They agree with Haacke, and therefore propose the 

 provisional abandonment of Kolliker's genus Heteroxenia. 



Bourne (1895) observed in his new species, Xenia Garciae, 

 numerous imperfect polyps or buds in all stages of growth at 

 the edge of the polyp-bearing summits of the stems. He re- 

 marked that " these are not siphonozooids, but stunted or 

 developing polyps.^' 



Bourne also described a specimen which he referred pro- 

 visionally (being unable to procure KoUiker's original descrip- 

 tion) to the species Heteroxenia Elizabeth se. In his 

 description were noted — 



