Eucosmodontidae
Scientific classification
Kingdom: Animalia
Therapsida
Class: Mammalia
Order: Multituberculata
Family: Eucosmodontidae
Genera
  Eucosmodon
  Clemensodon
  Stygimys

Ref.

Eucosmodontidae is a poorly preserved family of fossil mammals within the extinct order Multituberculata. Representatives are known from the Upper Cretaceous till the Lower Eocene of North America, (and apparently the Paleocene to Eocene of Europe).
For the technically minded, this family is part of the suborder of Cimolodonta. They might be related with the Djadochtatherioidea but without further finds, this remains unclear. Other than for a partial snout, fossil evidence is presently limited to teeth.

Taxon: Eucosmodontidae Jepsen, 1940
Remarks: Some authors interpret this version of Eucomsmodontidae and Microcosmodontidae as being subfamilies, rather than families.

Page reference: Page reference: Kielan-Jaworowska Z & Hurum JH (2001), Phylogeny and Systematics of multituberculate mammals. Paleontology 44, p.389-429.

(This information has been derived from [1] MESOZOIC MAMMALS; Eucosmodontidae, Microcosmodontidae and Taeniolabidoidea, an internet directory. As that's my webpage, there are no issues of copyright. Trevor Dykes)