﻿290 



DI?. STANLEY SMITH OX AZJLJNA EOTtFOBMJS, [vol. lxxii, 



V. Aulixa, gen. nov. 

 Family ? PhiiHpsastraeidae. 



The structure of Aulina is in most respects similar to that 

 of Phillipsastreea, but it appears to cany to a further stage of 

 development the septal characters peculiar to the latter genus. 



Generic Characters. 



The corallum is massive, and the corallites are united by their 

 extrathecal tissue. All the septa dilate at the theca, and those 

 of the major cycle again dilate at their axial edges, in such a 

 manner as to fuse together and so to form a cylindrical wall or 

 tube within the theca (see fig. 4, p. 292). 



Stability of character is a feature strongly maintained. 



Genotype : Aulina rotiformis S. Smith. 



Type-specimen of A. rotiformis. The holotype has been cut in 

 two : one half is in the British Museum (E. 17497), and the other 

 in the Sedgwick Museum, Cambridge. 



Aulixa rotiformis. sp. nov. 



1910 PMllipsastraa radiata (Martin), S. Smith, Trans. Nat. Hi<t. Soc. 



Northumberland, &c. n. s. vol. iii, pt. 3, pp. 629-30. 

 1912. PJiillipsastraa radiata (Martin), E. J. Garwood, Q. .1. G. S. vol. lxviii, 



pp. 542-43. 



1916. Aulina rotiformis S. Smith, Abs. Proc. Geol. Soc. No. 995, pp. 2, 3. 

 Aulina rotiformis was recorded as Phillipsastrcea radiata from 

 South Northumberland by myself and from Hurdorthwaite Moor 

 (North Yorkshire), by Prof. E. J. Garwood, in the publications 

 above cited. No description of the form was given in either 

 paper. I remarked that the form Avas plentiful in and charac- 

 teristic of the Fell Top Limestone around Harlow Hill, while 

 Prof. Garwood stated that it was somewhat abundant in the 

 Botany Beds on Hurdorthwaite Moor and that he had not found 

 it in situ at any other horizon. 1 



External Characters. 



The corallum is massive, and is typically depressed in form. 

 The corallites are not defined b}- epitheca ; consequently, the only 

 epithecal development present is that external to the whole colony. 



The upper or distal surface of the corallum is generally 

 flattened and fairly uniform. The theca? measure about To mm. 

 in diameter ; they are near together and regularly arranged, as 

 compared with those of Orionastreea . lying 1 to 3 mm. apart. 2 



1 He recorded the finding- of an angular and unworn specimen of Phillips- 

 astrsea radiata resting upon the Tyne Bottom Limestone in High Cup Gill 

 and of a cast of the same from the Drift of Ravenstonedale. The High-Cup 

 Gill specimen was correctly identified, and therefore not Anlvna, but Orion- 

 astraea. 



2 In one of the specimens collected from the Botany Beds the calices are 

 larger and proportionately more widely separated, and the surface more 

 mammiferous, than in the Harlow-Hill material. 



