690 Transactions of the Society. 



to suggest another possible explanation. For this purpose let us 

 consider the following species : — 



1. Juncella juncea. 



2. Scirpearia flagellum. 



3. Suberogorgia kollikeri. 



4. Lophogorgia lutkeni. 



5. Juncella trilineata. 



6. Scirpearia quadrilineata. 



7. Calyptcrinus allmani. 



Juncella juncea and Scirpearia flagellum, in common with all 

 other Juncellids, except Juncella trilineata and Scirpearia quadri- 

 lineata, have the polyps disposed in two longitudinal series separated 

 by two diametrically opposite longitudinal bare tracts. 



In Suberogorgia kollikeri the polyps arise from all parts of the 

 stem and branches, with the exception of a narrow, often wavy, 

 portion on either side of the cylindrical axis. 



In Loplwgorgia lutkeni the polyps are numerous and occur on 

 both sides of the stem and branches ; the central portion of both 

 the main stem and branches on both surfaces are destitute of polyps. 



Again, the stem and branches are flattened in the plane of 

 branching and are marked on the flat sides by a narrow winding 

 groove or furrow, which is continued along the flattened surfaces 

 of the secondary branches. The polyp-bearing surface is divided 

 into two lateral bands by means of the two grooves. 



In Juncella ti'ilineata polyps arise in three different bands, 

 leaving three narrow bare strips, each of which has in its centre a 

 slight rib or keel. 



In Scirpearia quadrilineata the polyps are grouped in four 

 definite longitudinal series separated by four bare spaces. 



In Calgpterinus allmani there is a bare tract on one side of the 

 colony, otherwise the polyps occur all round. 



In Hicksonella the verruca? are all prominent, and arranged irregu- 

 larly on two-thirds of the circumference of the stock, leaving a bare 

 tract on one side free from verruca 1 for the whole length of the stock. 



A detailed discussion of the question under consideration with 

 regard to the various species of Juncellids has been given in the 

 " Eevision of the Gorgonellids," so that it is only necessary here to 

 recapitulate the conclusions which have been there stated. 



1. In all species of Juncellids, so far known, the polyps are 

 disposed in a certain number — two, three or four longitudinal 

 series which are separated by a similar number of bare tracts. 

 This number is constant for the species. 



2. There is always a definite number of nutrient canals larger 

 than the others, which are known as the main longitudinal canals. 



3. These main canals always correspond in number and position 

 to the bare tracts. 



