In other forms genital ducts and nephridia coexist in the same segment.
In both Oncidiidae and Pecten the pallial eyes have probably been developed by the modification of tentacles, such as coexist in an unmodified form with the eyes.
The rupture of the concordat at once terminates the obligations which resulted from it on both sides; but it does not break off all relation between the church and the state, since the two societies continue to coexist on the same territory.
For in man self-determination and mechanical determination by empirical motives coexist, and only in so far as he belongs and is conscious of belonging both to the sphere of sense and to the sphere of reason does moral obligation become possible for him.
Identity and difference among ideas, as when we say that " blue is not yellow "; or (b) with mathematical relations, as that " two triangles upon equal bases between two parallels must be equal "; or (c) in assertions that one quality does or does not coexist with another in the same substance, as that " iron is susceptible of magnetical impressions, or that ice is not hot "; or (d) with ontological reality, independent of our perceptions, as that " God exists " or " I exist " or " the universe exists."
We might consider that matter and aether can coexist in the same space; this would involve the co-existence and interaction of a double set of properties, introducing great complication, which would place any coherent scheme of physical action probably beyond the powers of human analysis.