58 
CATALOGUE -OF ECHIXIDA. 
d. Lateral ambulacra similar , petaloid sunken ; lateral fascicle 
extending under the vent ; subanal fasciole none. 
12. Desoria. 
Shell ovate, thin, convex; vertex excentric, anterior; am- 
bulacra narrow, sunk into a rather deep groove ; the anterior 
lateral pair rather transverse, the posterior longitudinal ; the 
anterior odd ambulacra not so much sunk, each line formed of 
only one series of small double pores ; surrounded by a very 
sinuous peripetalous fasciole, giving a lateral fasciole which 
extends under the vent, without any distinct subanal fasciole 
or subanal disk ; mouth anterior ; vent moderate, covered with 
small scales; ovarial pores four, in front of the madreporiform 
plate. 
Desoria, Gray , Ann. & Mag. N. H. 1851. 
Shaped like Brissus , but distinguished by the presence of 
the lateral fasciole, and the absence of the subanal fasciole and 
disk ; and from Agassizia by the sunken ambulacra. 
1. Desoria Australis. 
Ovate; pink. 
Desoria Australis, Gray , Ann. & Mag . N. U. 1851. 
Hab. Australia. Fiinder’s Island. 
a,b. Pale pink; without spines. Van Diemen’s Land. 
Presented by R. Gunn, Esq. 
c, d. Pale pink ; without spines. Presented by Joseph 
Millington, Esq. 
Var. 1. Vertex high, oblique; areolated, brown, with pale 
reddish edges to each of the tessera ; like Humph. Amb. t. 24, 
f. 1 ] t. 6, f. 2. 
e. Van Diemen’s Land. Presented by Joseph Millington, 
Esq. 
/. Oblong, with spines. Island of Musbate. Mr. Cuming’s 
Collection. 
13. Tripylus. 
Shell cordate, rather depressed ; tubercles equal ; apex cen- 
tral ; ambulacra sunken ; the lateral radiating, the anterior pair 
elongated, the hinder pair short; the odd anterior one deep, 
forming a distinct anterior groove, with a series of small double 
pores on each side ; surrounded by a very flexuous peripetalous 
fasciole, with a lateral fasciole separating from it and descending 
under the vent ; ovarial pores three or four. 
