1 Dorsum covered by large tubercles or papillae, often with sediment particles.. 2
– Dorsum covered by small globular papillae........... 6
2 Dorsal tubercles soft, clavate with a thin base........... 3
– Dorsal tubercles tough, digitate or rectangular, with a wide base. F. ockeri n. sp.
3 Notopodial lobes compact, individual papillae mucrones not visible.... 4
– Notopodial lobes hirsute, individual papillae with mucrones free. F. gourdoni (Gravier, 1906) n. comb.
4 Dorsal tubercles of two different sizes; neurohook handle with three longer articles, basal short, others slightly longer.. F. claparedei (de Saint-Joseph, 1898) n. comb.
– Most dorsal tubercles clavate................ 5
5 Notopodial lobes with little sediment (living in sponges); 20–22 papillae per transverse row per segment, all shorter than notopodial lobes.. F. lighti n. sp.
– Notopodial lobes with abundant fine sediment (living in sandy bottoms or kelp holdfasts); 12–14 papillae per transverse row per segment, most about as long as notopodial lobes, some longer... F. papillosa (Essenberg, 1922) n. comb.
6 Dorsal papillae without sediment particles; notopodial lobes thick. F. pruvoti (Fauvel, 1930) n. comb.
– Dorsal papillae with sediment particles; notopodial lobes thin F. berkeleyorum n. sp.