28 



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 

 striae and spines from a third of a line to half a line apart. Some individuals appear to be 

 simple, but most increase 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. 



H, proliferum is readily distinguished from the other species of the genus, by its elongated 

 cylindrical form ; its increase by lateral gemmation, and its social habit. Not only is the species 

 composite, in the sense that most of the individuals produce lateral buds, but, so far as I have ob- 

 served, it is strictly social, vast numbers of individuals occurring together, growing vertically side 

 by side butseparate. 1 have not seen more than one or twobuds borne by a single parentcorallite, 

 and calicular gemmation appears to be unknown. The only other Heliophi/lhim known to increase 

 . by lateral gemmation is H. sub-ccespitosum, but this is a very much smaller form, and is solitary 

 in its habits. Detached individuals of H. proliferum in which budding appears not to have 

 taken place, may usually be recognised by their great length and almost strictly cylindrical 

 form, there being little or no increase of diameter as the cup is approached. Large indi- 

 viduals 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. 



Locality and Formation. Extraordinarily abundant in one bed in the Corniferous Lime- 

 stone of Ridgeway. 



21. HELIOPHYLLUM ERIENSE (Billings). 



Heliophyllum Eriense (Billings) ; Canadian Journal, New Series, Vol. IV. p. 124. 



Corallum elongate, turbinate, straight or curved. Septa from seventy-four to one hun- 

 dred and fifty in young and old individuals respectively. Septa extending to the centre of the 

 calice carrying on their sides delicate arched striae separated by intervals of from a quarter of 

 a line to a sixth of a line. Free edges of the septa " denticulated with from five to seven short 

 spines in the space of one line." Epitheca with sharp annulations and encircling ridges of growth. 



This species is readily distinguished by "' the closeness of the arched striae on the sides 

 of the septa, and the minute dent ; culation on their free edges" (Billings). H. Eriense is 

 exceedingly variable in its dimensions, varying in length from an inch and a half up to nearly 

 a foot, and as regards the diameter of the calice from an inch and a quarter up to three inches 

 and a half. The calice is deep, and there appears to be an obscure septal fossula on one side. 



Locality and Formation. Corniferous Limestone, Lot 29, Con. ,'i, Walpole ; and Port 

 Colborne. Very rare. 



22. HELIOPHYLLUM COLLIGATUM, (Billings). 



(Plate V. Figs. 3, 3a). 

 lleliophyllum colligatum (Billings); Canadian Journal, New Series, Vol. IV. p. 126. 



" Corallum forming large masses of long slender corallites, which are connected together 

 at intervals of from two to four lines by periodic expansions of the cup ; radiating septa about 

 fifty-two ; diameter of the corallites where constricted five lines ; and of the expanded cup 

 six to ten lines. Among the full grown there are interspersed some that are immature and of 

 smaller size. The cup is shallow, the sides of the septa striated with from six to eight arched 

 ridges in one line, and their free edges denticulated with the same number of minute spines. 

 In the central area the transverse diaphragms are well developed, and sometimes constitute 

 a pseudo-columella, which exhibits itself in the shape of a small elevated boss in the centre of 

 the cup" (Billings). 



This species cannot be confounded with any other. It is remarkable amongst the typical 

 species of this genus in being compound instead of simple ; and it has the tabulae unusually 

 well developed, constituting a central area into which the septa, as a rule at any rate, do not 

 enter. The epitheca is transversely ringed with annulatioos of growth, and, in the periodic 

 expansions of the cup, with numerous fine encircling striae, which are crossed by the longitu- 

 dinal lines which mark the position of the septa. As pointed out by Mr. Billings, H. colli- 

 gatum forms a transition between Heliophyllum and Phillipsastrceea. 



Locality and Formation. Corniferous Limestone of Rama's Farm, Port Colborne, and 

 Walpole. 



