The Echinoid Directory

Cionobrissus A. Agassiz, 1879, p. 206

[=Cionobryssus Meissner, 1903, p. 1343 (nomen vanum); = Cisnobrissus Bather, 1909, p. 22 (error)]

Diagnostic Features	Test ovate with shallow anterior sulcus that continues to peristome. Subanal region projecting as a heel. Apical disc ethmolytic, with 4 gonopores. Apical disc offset towards anterior. Anterior ambulacrum narrow and shallowly sunken; groove deepening towards peristome. Pore-pairs in anterior ambulacrum small and undifferentiated; no funnel-building tube-feet present. Other ambulacra petaloid, the anterior pair widely divergent, almost set at 180 degrees. Petals hardly sunken and straight-sided. The posterior pair a little longer than the lateral pair. Periproct on posterior truncate face, above prominent subanal heel. Peristome small and forward-facing. Labral plate longer than wide. Sternal plates also very narrow and elongate. Scattered large primary tubercles with weakly sunken areoles within peripetalous fasciole. Coarse aboral tubercles and spines bounding anterior groove. Fully formed peripetalous and subanal fascioles. Subanal fasciole shield-shaped and surrounding subanal heel, Peripetalous fasciole not indented in interambulacral zones.
Distribution	Recent, Indo-Pacific. Continental slope - ?infaunal.
Name gender	masculine
Type	Cionobrissus revinctus A. Agassiz, 1879, p. 206, by original designation.
Species Included	Only the type species.
Classification and/or Status	Spatangoida, Micrasterina, unnamed family. Monotypic.
Remarks	Easily distinguished from other brissids by its prominent subanal heel and well-formed groove leading to the peristome adorally. Resembles Anametalia, both having a distinct subanal heel. Anametalia, however, differs in having a shallower and much less distinct groove on the oral surface leading to the peristome and a shorter labral plate than does not extend beyond the first ambulacral plate. Migliorinia has a similar strong goove leading to the peristome, but the peristome is more central and there is no subanal projection. Agassiz, A. 1879. Preliminary report on the Echini of the exploring expedition of HMS Challanger, Sir C. Wyville Thomson, chief of civillian staff. Proceedings of the the American Academy of Arts and Sciences 14, 190-212. Mortensen, T. 1951. A monograph of the Echinoidea. V Spatangoida 2. C. A. Reitzel, Copenhagen.