220 J. H. ASHWOIiTH. 



Autozooids. — Spicules are numerous in the ectoderm of all parts of 

 tLe body of the autozooid, and are very numerous in the ectoderm of 

 the outer face of the tentacles. They are also present in the pinnules. 

 They are similar in size and shape to those of Xenia Hicksoni. They 

 are whitish or bluish white by reflected light, but of a reddish-brown 

 tinge by transmitted light. Nematocysts are exceedingly scarce and 

 difficult to find. They measure 9 /j. in length and 2-| jjl in width. The 

 ectodermic muscles of the tentacles are well developed ; the muscle 

 band of the oral face is very much thicker than that of the aboral face. 



The oral disc of each polyp is slightly contracted, producing a funnel- 

 shaped depression leading to the mouth. The stomodseum is only 1 mm. 

 to 1*5 mm. long, and is wrinkled or folded trans 7ersely. It bears a 

 ventral groove or siphonoglyph, the cells of the lower half of which 

 bear moderately long flagella. There are the usual eight mesenteries, 

 bearing rather feebly developed retractor muscles on their ventral faces. 

 Only the dorsal mesenteries bear mesenterial filaments, and these have 

 a typical course and structure. Owing to imperfect preservation it is 

 impossible to say anything definite about the cells of the other mesen- 

 teries, but no ventral or lateral mesenterial filaments are visible. 



The ccelentera of the polyps may be traced a considerable distance 

 into the stem, those of the primary polyps being continued down to the 

 base of the colony. In the upper portion of the stem the ccelentera 

 contain many ova, each of which is surrounded by an endodermic 

 follicle attached to the mesenteries. The largest of these ova measure 

 *3 mm. to "4 mm. in diameter. 



Siphonozooids (Fig. 39). — Spicules are not so numerous in the ecto- 

 derm of the zooids as in that of the polyps. 



The stornodseuin is very badly preserved in most of the specimens. 

 A few of the zooids situated near the edge of the summit, however, are 

 rather better preserved, and two of these (S 3 and S 7 in the table, 

 p. 218) have been sectioned and the stomodseum examined. In the 

 zooid 2 - 3 mm. long the stomodseum measures '6 mm., and shows a well- 

 marked siphonoglyph, the cells of the lower '2 mm. of which bear 

 flagella. The other specimen (S 7 in table, see also Fig. 39) is 5 mm. 

 long. Its stomodseum measures -8 mm long, and the cells of the lower 

 •4 mm. of the siphonoglyph bear flagella. 



Thus both autozooids and siphonozooids of this specimen possess a 



