50 T. S. Hall: 



segments of the opposite sides touching at the apex. The outer 

 ends of the postero-laterals are half the distance apart that the 

 outer ends of the antero-laterals are. Actinally the ambulacra 

 are broad and bare. Peristome crescentic. Labrum not 

 prominent. 



Peripetalous fasciole crossing the anterior groove at about half 

 the diameter of the test from the apex. It runs back parallel to 

 the groove for about 8 mm., and then bends out to the outer end 

 of the antero-lateral petal. Thence it curves inwards following 

 the curve of the petals, and betvveen the outer ends of the pos- 

 terior petals is straight. Its form is almost exactly that figured 

 by A. Agas.siz for B. lyrifera in his " Revision " (pi. xix., tig. 9). 

 The subanal fasciole is concave above. The presence of an anal 

 branch is doubtful. 



There are four perforate basals. 



Measurements. 



Length. Breadth. Hei.ht. ^^^^f • ^nt .at. ^ Apical^Syst^^ 



1.-46-41-24-6-6-27 

 2. - 47 - 41 - 23 - - - 7 - 27 



The fine calcareous matrix is closely adherent to all the 

 numerous specimens before me, and many are crushed and broken. 



Professor R. Tate has recorded Toxobrissus sp. from our Older 

 Tertiary. This is a synonym of Brissopsis, and the record 

 perhaps refers to the present species. 



In the curvature and mutual relationships uf the ambulacral 

 petals and in the shape of the peripetalous fasciole, the affinities 

 of the present species are not with such an Eocene form as the 

 Sindian B. sufflatus, Duncan and Sladen, but rather with the 

 existing B. lyrifera and B. luzonica, aud more especially with the 

 latter. From it, however, it is distinguished by the closer 

 approximation ^f the outer ends of the postero-lateral petals and 

 by its more broadly oval form and less pointed posterior end. It 

 also closely resembles B. crescenticus, Wright, from the Malta 

 Oligocene, but is easily separable by the closer approximation of 

 the posterior petals posteriorly, and by the greatest width being 

 behind the apical system, and not in front of it. 



