158 ZOOPHYTES. 



nor caa I identify the present subject as the Sertularia filimla, or any 

 other yet described. Therefore the appellative it now receives must prove 

 either provisional or permanent, according as future observation shall de- 

 termine. 



The shades of distinction separating some of the zoophytes are small ; 

 their own formation is variable and indefinite, and they are in so many 

 varieties, that very erroneous conclusions may lead us to diversify species, 

 while the subjects passing through slight discrepancy of structure shall at 

 length merge in one. 



The Sertidtiria abietinula generally appears from one to two, or per- 

 haps three inclies high. Branches originate near the root, diverging and 

 diminishing after the fashion of the former, and, like it, they are provided 

 with few subordinate parts. — Plate XXV. figs. 6, 7. The whole are bor- 

 dered by low denticles or cells, nearly in pairs, from which hydrae, with 

 about 18 tentacula, are displayed. Branch enlarged, fig. 8. 



Irregular articulations subdivide the inorganic parts, comprehending 

 five or six pair, or sometimes only a single pair of cells. The contrac- 

 tion of the stem at the articulation, under the pair of cells where it is 

 formed, is considerable. 



For the most part, simple ampullate vesicles are dispersed over the 

 branches, wherein the elements of the progeny are generated. These are 

 seen as a bright yellow corpusculum of irregular form. — Plate XXV. 

 figs. 9, 10. 



When a specimen had been a few days in my possession, the vesicles 

 under that aspect discharged their whole contents, perhaps prematurely, 

 which now exactly resembled, in all respects, what is above described of the 

 premature discharge from the vesicles of the Sertularia polyzonias. A 

 transparent gelatinous mass remained adhering to the orifice of the vesicle, 

 among which, instead of a single object as I had previously supposed, there 

 appeared from one to six vivid yellow corpuscula, still of somewhat irregu- 

 lar form. The substance wherein they were imbedded was scarcely percep- 

 tible ; and, indeed, at one particular place, unless for the vicinity of the 

 yellow corpuscula to the branch bearing the vesicle, the connection of the 

 jelly with its mouth could not be known. — Fig. 11, a. 



