S59

Notes on the Genera Ommatogramma, Spongurus and Spongocore

According to Haeckelian systematics the genus Ommatogramma belongs to the Family Euchitoniidae and has a central structure composed of concentric rings. However, Ehrenberg's (1872b) illustration of the type species, O. naviculare, does not show such a structure. Therefore, Petrushevskaya (1975) has correctly moved the genus to the Family Sponguridae. She also synonymized it with Spongurus, Spongocore and Spongocorisca. However, in the same publication, Petrushevskaya noted that Spongurus pylomaticus seems sufficiently different from Ommatogramma dumitricai as to require a "special (new) genus", and so she retained the designation S. pylomaticus.

Spongurus (?) sp. (herein) had been placed in the genus Spongurus as a matter of convenience (cf. Petrushevskaya, 1967 and Ling et al., 1971), but has a distinctive spiral structure.

Spongocore puella has quite a different shell outline from O. dumitricai, but a similar spongy construction.

Since none of the above mentioned species has been studied in the context of their relationship to each other, it seems unwise to change generic assignments mechanically. Hence, Petrushevskaya's generic synonymy is not used for the time being and familiar terminology is retained herein.