TURBINARIA. 17 



1. While tlie tendency to project at all is of importance, little reliance can be placed 

 upon the height to which the calicles protrude, every grade of protrusion being found in one 

 and the same colony ; in some situations the calicles are on long projections, in others, they 

 are all immersed. 



2. The second point is of more importance, viz. the character of the protrusion of the 

 coenenchyma when it does occur. As this must depend upon the activities of the polyp, it 

 brings us — one would expect — more witliin reach of the inherited tendencies of the living 

 organism, and therefore of characters of some genealogical importance. Unfortunately, the 

 characters are not always very well marked. Among the various forms which the projecting 

 calicles may assume, the following may be noted : — 



a. Cylindrical, or acutely conical, with thin margin round the fossa, the aperture 

 practically occupying the whole of the top of the cylinder. 



h. Cylindrical, with very tliick margin round the fossa, the aperture not filling the 

 whole top of the cylinder. 



c. Bluntly conical, which passes into 



d. Hemispherical. 



Sc]}ta— Number. — The number of the septa varies in a most bewildering manner, but it 

 seems to range near some multiple of 6. Excepting when the divergence is very great, no 

 value can be attached to it for the purposes of classification. 



Character of Septa. — In some cases, they form a system of faint vertical ridges, running 

 down to the columella round a widely open fossa. In the other extreme, they stand out so 

 far as to leave but a minute pinhole-like fossa in the centre. Between these extremes, one 

 finds every variation. I have found it useful to imagine a half-radius circle, by which to 

 specify these variations. The septa fail to reach this circle, reach it, or project beyond it. 

 This measurement is both artificial and rough, yet it is, at the same time, the best and 

 the simplest I coiild devise. 



I have not found the toothed edges of the septa, or their granulation, of much assist- 

 ance in classification, although the point deserves, perhaps, more attention than I have given 

 it. The thickness of the septa is of some importance, inasmuch as thick septa mean as a rule 

 very narrow interseptal loculi. Further, the descent of the septa into the fossa, whether 

 vertically or slantingly, should be noted. In the former case, the fossa is cylindrical ; in the 

 latter, funnel-shaped. 



Tlie Fossa. — The space bounded by the septal ridges may be ■wide and cylindrical ; narrow 

 and cylindrical, or funnel-shaped ; deep or shallow. Great variations in the depth of the calicles 

 may be found on one and the same coralhim. 



Interseptal Loculi. — These yield what I think may be important characters. They may 

 be limited peripherally or not limited, i.e. open to and continuous with the furrows marking 

 the surface of the cajnenchyma. When limited peripherally, their contour may be narrow 

 and oblong, or nearly square, sliort petaloid or long petaloid. And lastly, the peripheral 

 boundary of the interseptal loculi may be very irregular, here open and there closed. This 



D 



