Prof. H. A. Nicholson — New Devonian Fossils. 59 



duced by parietal gemmation are few in number (generally one or 

 two, rarely three), and are directed upwards, nearly in the direction 

 of the parent corallite. In some cases calicular gemmation appears 

 also to occur. 



H. sub-ccBspitosum has a general resemblance to Cyatliophyllum 

 ccBspitosum, Goldf. ; but the presence of well-marked septal stri» 

 and septal spines, proves it to be a true Heliophyllum. The latter 

 species, also, is " fasciculated or astreiform," and increases princi- 

 pally by calicular gemmation, whereas H. sub-ccespitosum never pro- 

 duces sufficient buds to form aggregations of any size, and the in- 

 crease is principally or entirely by parietal gemmation. It is, further, 

 distinguished from the other forms of Heliopliyllum by its compara- 

 tively small size, its cylindrical form, and its mode of growth, stand- 

 ing in this last-mentioned respect almost alone among the species of 

 the genus. H. proliferum, Nich., increases in the same way, but is 

 a much larger species, and is distinguished by other characters as 

 well. 



Young individuals of JI. suh-caespitosum are usually strongly 

 nodulated with irregular growth-swellings, and have a length of 

 from half an inch to an inch, with a diameter at the cup of from two 

 to three lines. Large individuals have a length of from two to three 

 inches, with a diameter at the calice of from eight to ten lines. 



Locality and Formation. — Common in the Hamilton Shales of 

 Bartlett's Mills, near Arkona Township of Bosanquet. 

 Heliophyllum proliferum, Nicholson. 



Spec. char. — Corallum large, simple or compound ; growing socially 

 in particular localities, where numerous individuals occur together, 

 nearly in contact, though not organically connected. Form cylin- 

 drical, with numerous irregular growth-swellings in the majority 

 of examples. Calice moderately deep, with about sixty septa at a 

 diameter of fourteen lines. The septa are unequally developed, and 

 extend to the centre of the calice, where they are usually more or 

 less twisted, and are sometimes elevated in the form of a central 

 boss. Arched septal striee and spines from a third of a line to half 

 a line apart. Some individuals appear to be simple ; but most in- 

 crease by the production of lateral buds, which spring from the 

 parent corallite in an obliquely ascending manner. The epitheca 

 exhibits numerous encircling striae and annulations of growth. 

 Large individuals have a length of seven or eight inches or more, 

 with a calicine diameter of an inch and a half, and a similar diameter 

 throughout. 



M^ proliferum is readily distinguished from the other gpecies of the 

 genus by its elongated cylindrical form, its increase by lateral gem- 

 mation, and its social habit. Not only is the species composite, in 

 the sense that most examples produce one or moro lateral buds, but, 

 so far as I have observed, it is strictly social, vast numbers of 

 individuals occurring together, growing vertically, side by side, but 

 separate. I have not seen more than one or two buds borne by a 

 parent corallite, and calicular gemmation appears to be unknown. 

 The only other species of Heliophyllum known to increase by lateral 



