TABLE 1.

Summary of the pattern of association between virus envelopes (presence or absence) and hosts (with and without cell wall) among 101 virus families^a

Host	No. of virus families
	Nonenveloped	Enveloped	Total
With cell wall	49	10	59
No cell wall	30	34	64
Total	79	44

^aThe S-layer of Archaea has been treated as cell wall. Note that some virus families can infect hosts with and without cell wall and are therefore present in more than one category.