56 r. m. pexcax ox the echin'oderm-vta of the 



very small, and nearly central; there are four generative pores, 

 the posterior pair being the widest apart, and the madrepohforni 

 body passing between them. The peripetalous fasciole is narrow, and 

 incloses a cordiform space. Tubereulatien small everywhere : but 

 there are larger tubercles grouped within than without the fasciole. 

 and thev become smaller towards the sharply rounded ambitus. 

 The actiiiosome is well in front, the anterior part being sunken ; 

 the phyllodes are distinct : the plastron is nearly smooth : and the 

 tubcrculation of the actinal surface, which is throughout small, 

 becomes larger remotely from the ambitus. 



Height T ^ inch, length 1 T ^ inch, breadth ly 4 ^ inch. 



Locality. — Section 1 mile west of the mouth of the Sherbrook 

 river, lower part of cliff. 



The small tubercles, the depressed shape, the equal size of the 

 petals, the very thin fasciole. and the far forward mouth distinguish 

 this species, which I have dedicated to the excellent palaeontologist 

 Prof. Laube. 



The next group of Australian Echini is very characteristic of the 

 Tertiary marine deposits of the southern provinces. Members of it 

 have been found in the corresponding formation of Xew Zealand. 

 in the later Tertiaries of Java, and in the Eocene. Miocene, and 

 Pliocene strata of Europe. 



Genus Lovexia. Desor, 1847. 

 Syn. Hcmipatagus, Desor. 1858. 



Desor originated the genus Hcmijwtagus amongst the fossil Echini 

 in 1S-3S. to include some species of the old genus Spatangvs, which 

 had the following characters * : — 



" Little Urchins with large tubercles on the interambulacral area-. 

 like true Sj-Hitangi. but with this difference, that none are found in 

 the odd or posterior interambulacrum. The plastron is smooth, as 

 if rubbed : the petals are long and spread cut ; there are four genital 

 pores, and there are no fascioles." 



This diagnosis separated the group from Spatangus. which has a 

 subanal fasciole. and tubercles in all the interambulacral areas — and 

 distinguished it from E'tpatagus. which has its posterior interambu- 

 lacrum without tubercles, and a subanal as well as a peripetalous 

 fasciole. The distinctness of the group was evident enough, al- 

 though the generic value given to it was a matter of doubt. 



Grayt had in 1855 described a hue recent Echinus under the 

 new generic title of Ala ret ia. and his diagnosis brought it into close 

 relation to Hcmiijatagus. Desor. It has the generic characters and, 

 in addition, an indistinct subanal fasciole : but the test is flattened. 



In 1S73 A. Agassiz noticed the close resemblance of the Hemi- 

 patagi and Alaretia, and. considering the subanal fasciole of no 

 moment, determined their identity. 



* ' Synopsis ties Echinides." p. 410. 

 + Cat. Eec. Echini. Brit. Mas. 



