Ascodlctjon «nJ Ilho[)alonana. 81 



sliales were searclied with the same minute care that I have 

 bestowed upon those furnished to me by Mr. George Maw. 

 Then, again, ^. siluriense and^. radicifonne were the tirstfruits 

 of my hibours; and A. jiliforme was the result of closer exa- 

 mination. As with me so with others, because the matured 

 forms will, I fancy so at least, be considered by the student of 

 micropalajontology as by far the most important as initial 

 stages in an inquiry like the present one. Another conside- 

 ration is with me of much greater weight than any previously 

 given. It may be, after all the care that I have exercised in 

 thus tracing the origin and development of a colonial growth, 

 that some few facts or fossil illustrations may have been over- 

 looked, and it may be necessary at some future time to limit 

 the type now characterized as A. filifomie. If this should 

 happen, the suppressed names would have to be restored. 



In his observations on A. stellatum Prof. Nicholson remarks 

 {op. cit. p. 465) , that in its youngest stage the organism " pre- 

 sents itself simply in the form of scattered oviform or pyriform 

 calcareous vesicles attached to the exterior of foreign bodies. 

 When mature it consists of similar vesicles combined into 

 clusters.*' I do not doubt the accuracy of Prof. Nicholson's 

 observations, though I cannot, on the whole, endorse them from 

 my own labours : all the vesicles are united to the filiform 

 thread, though in a few isolated instances " apparently " they 

 are not so. I have examined a large series of A. filiforme for 

 the purpose of putting the observations of Prof. Nicholson to 

 the test, and I am consequently unable to confirm his views. 

 In his description of fig. (3, pi. xix. {op. cit.), the author says, 

 " Four young vesicles (?) of the same {A. stellatum) &c. ;" the 

 vesicles are not foraminated, as in the other figures (2 to 5^ 

 pi. xix.) , and in this special feature the Ontario vesicles are allied 

 to, though not identical with, those shown in fig. II. of the 

 present paper as gradational stages in the development of>4, 

 Jiliforme, Vine. 



2. Ascodictyon stellatum, Nich. & Etli., jun., 

 var. siluriense, Vine. 



=Ascoclictyon stellatum, Vine, Quart. Journ. Geol. Sue. Nov. 1831, 



p. 618. 

 = Ascodictt/071 stellatum, var. siluriense, Vine, Q. J. G. Soc. Feb. 1882, 



p. 52. 



The details of this species have been given in the works 

 referred to above. 



