^12 



They are prominent, equal, and extend to the base. Those at 

 .the edges follow the outline of the corallum, and are thus 

 doubly cui-ved, while the more central ones become nearly but 

 not quite straight. 



Tlie corallum is from 5 mm. to 7mm. in height, and the calice 

 from 5 mm. to 6.5 mm. long by 4 mm to 5 mm. broad. In the 

 largest example the base is 5 mm. longer than the calice. 



Locality, ttc. — Like the preceding species, from the Adelaide 

 bore. Collected by Professor Tate. 



PlaCOtPOChUS Pueblensis, spec, nov. Pi, il., figs, la, 6. 



The corallum is moderately taJl, ciu-ved, and tapers to a 

 rounded and almost pointed base. There is a slight constric- 

 tion about two^thirds from the summit, below which a faint 

 ridge marks the concave surface of the curve. The calice 

 is almost but not quite circular, and throughout its length 

 transverse sections of the corallum are approxiniMely circular. 



Tlie septa are exsert, slender, and in six systems, with four 

 < complete cycles. The primaries and secondaries are equal, 

 and the remaining orders become gradually thinner as well as 

 ■shorter ; all are sparingly granular. 



The axial fossa is deep centrally, and is traversed longi- 

 -tudinally by a prominent columella, which, instead of being 

 a single lamella, as in Placotrochi generally, is double, with 

 'One division rather shorter than the other. This character is 

 certainly not due to fission since the lens shows delicate 

 granules on the inner side of each lamina. Probably the divi- 

 sion does not extend very far down, and I should not be 

 suriprised to find examples with the columella single. There 

 is also a sliort, thin, buttress^like process from the lomger limb 

 of the columella and in a line with a secondary septum. 



Cost>8e corresponding to the principal septa are visible on 

 the wall as thin, slightly raised ridges. The wall is thin and 

 covered by a delicate shining epitheca ornamented by several 

 inconspicuous transverse folds which, near the calice, form 

 arched crests upon the costae. 



Height of icorallum, 17 mm. ; the diameters of the scai'cely 

 elliptical calice are respectively 10.5 mm. and 10 mm. 



Locality, &c. — •! collected the unique example of this species 

 on "The Ledge" at Spring Creek in 1899, and though the whole 

 section has been since searched over and over again no other 

 has been seen. Fortunately the specimen is exceptionally 

 well preserved. 



P. Pueblensis may be compared with P. corniculatus. mihi, 

 from the Adelaide bore, but the latter is compressed inferiorly, 

 .and has a more elliptical calice. 



