by w. n. benson, w. s. dun, and w. r. browne. 33!) 



Zaphrentis sp. indet. 



This is a large form, the calyx of which is about an inch in diameter, but is 

 stated by Dr. Smith (in a private communication) to be too poorly preserved to 

 admit of specific determination. It occurs in the small mass of limestone north 

 of the railway cutting four miles east of Currabubula. 



LiTHOSTROTION SP. 



Mitchell has reported finding a specimen of this genus, as recognised by 

 Sowerby, at Perimbungay, near the junction of the Peel and Namoi Rivers in 

 1831 (9). 



Amygdalophyllum etheridgei, gen. et sp. nov. (Plate xviii. ; Text-fig. 10.) 



The material for the investigation of this form consists of one specimen show- 

 ing the external form, but not that of the interior of the calyx, and four other 

 specimens from which have been obtained six transverse and two longitudinal 

 sections . 



The corallum (Plate xviii., fig. 1) is simple and turbinate, marked by slight 

 growth ridges, and rapidly increasing in diameter from apex to the bell-like 

 calyx. The length of the corallum must have been originally about sixty milli- 

 metres; its greatest diameter is forty-two. The external wall has been removed 

 for the most part, exhibiting the ends of the septa, which follow the plan, normal 

 to the Rugosa, of addition at four points. Where the coral has a diameter of 

 about ten millimetres there are thirty-eight septa visible, but where the diameter 

 is thirty-five millimetres the number of visible septa is increased to between ninety 

 and a hundred. Transverse sections show that the outer wall was thin, and very 

 slightly undulating, being apparently devoid of rugae and costae. The septa are 

 in two cycles, the longer reaching to the columella, the shorter extending to the inner 

 limit of the dissepimental zone. Septa of lioth cycles are stout, generally increas- 



Diamerer tOmm iStnm 55 mm 



Text-fig. 10.— Section of portions of the corallum of AtnygdalophylLuiu etheridgei, gen. 

 et sp. nov., to show the relation of the septa to the wall. Babbinboon. 



ingly so as they proceed further from the columella, this being especially marked with- 

 in the dissepimental zone. Generally the longer septa are more thickened than those 

 of the second cycle, but in some cases this distinction is not noticeable in the outer 

 parts. The septa of both cycles nearer the apical portion of the corallum pass 

 directly into the wall (Plate xviii.. f. 3; also Text-fig. 10a), but later they become 

 much thinner as they approach the wall, somewhat flexuous in some cases, and 

 supported from the wall by a number of obliquely placed lamellae (Plate xviii., 

 fig. 2, Text-fig. 106) In the sections of greatest diameter the septa may not 

 reach the wall at all, but near it branch out into the oblique supporting lamellae 



