CATALOGUE OF ECHINIDA. 13 
*** Genital pores 4, large , (posterior wanting ,) far apart and 
between the upper part of the ambulacra. Peronella. 
12. Laganfm Peronii, 
Ovarial pores 4, outside the apex of the ambulacra ; under 
surface concave ; vent some distance in margin. 
Laganum Peronii, Agassiz , Mon. Scutelle, 123, t. 22, f. 21-42, 
150 ; Agassiz S$ Besor, 1. c. 132. 
Scutella orbicularis, Lamk. Hist. iii. 282 ; Belong. E. M. ii. 677 ; 
Blainv. B. S. N. xlviii. 288 ; Besmoul. Tab. Syn . 232. 
Lagana orbicularis, Blainv. B. S. N. lx. 197 ; Zooph. 196. 
Hab. South Seas. 
a , b, c, d. Dark red, brown, some varied with some spines. 
New South Wales, Brisbane Water. 
e, f, g, h, i. Bleached, without spines. Australia, Flinders 
Island. Presented by Joseph Milligen, Esq. 
3. Arachnoides, 
Shell circular; discoidal thin; edge narrow ; ambulacral 
area gradually wider from the top ; the inter-ambulacral area 
narrow, and sunk below the level of the rest of the shell ; 
ambulacral petals triangular, series of pores gradually diverg- 
ing from each other, and wide open at the end ; tubercles 
of the ambulacral area in oblique parallel series, of inter- 
ambular area sporadic; inferior ambulacral grooves straight, 
not branched ; jaw very flat ; anus dorsal just above the lower 
margin. 
Scutella, sp., Lamlc. Hist. A. S. V. iii. 283 ; Besmoulin, Tab. 
Syn. 228. 
Arachnoides, Aqassiz , Monoq. Scutelle , ii. 94, 149 ; Sc Besor , Ann. 
Sci. Nat. 1847, 134. 
Echinarachnius, Leske ay. Klein , 218. 
Echinarachnius, sp., Fleming , B.A. 479; Forbes , Brit. Starfish , 
178. 
Echinodiscus, sp., Blainv. B. S. N. lx. 199. 
Echinarachnius (type), Gray, Ann. Phil. 1825 ; Agassiz , Prod. 
1. Arachnoides placenta. 
The outer ambulacral bands are only half as wide as the 
inter-ambulacral ones ; the space on the under side covered 
with the oblique series of pores only separated from each 
other by a narrow band. 
Arachnoides, Klein ed. Leske , 26, t. 20, f. a, b ; Klein GaU. 98, 
t. 11, f. a ; Ban. Cat. i. 424. 
Scutella placenta, Lamk. Hist , iii, 283; E. M. t. 143, f. 11—12 ; 
c 
