[82]

at same time making nearest approach to Perennibra Reptiles of all fishes.—

N. B Good observers yet dispute whether it is a fish.

The manner in which this Fish & ornithorhynchus (Owen says most anomalous since ornithorhynchus) being intermediate between great groups, shows affinities to more than these two great groups, is very interesting & I think explicable on my theory if we look at it as one descendant, which chance has preserved.—

[in margin:] Why, except from fewness of species, is not Lepidosiren a family equal to Osseous or Plagiostomous fishes.

Hence some Fish & Perennibran breathe by two means —

Means of passage from one state to another, as in Spiders

Now according to Waterhouse's theory. (leaving unknown Leipidosiren) Plagiostomous fishes are nearest to Reptiles amphibians (?) & Perennibranchia— nearest of Amphibians, now I suspect these do approach each other in the many points, viz lungs on the one hand (except lung-swimming bladder) & generative system on the others to Now I daresay no two species in these groups approach nearer in the points in which these two groups; but yet probably two genera do, namely sharks & Siren & yet how unlike these groups.

[82v]

Now if we take in Lepidosiren, then of all Fishes this genus or family approaches nearest to Amphibians, & of the latter, the Perennibranchiate approach nearest to Fishes — but in those points in which Lep. does approach Amphibians, it does approach nearest to Perennibranc: & in those points in which Perennibranchiate approach nearest to fishes, they do approach nearest to Lepidosiren.— Even perhaps Siren of Perennibran does approach nearest to Lepidosiren annectens or if Lepidosiren had contained many genera, it might have approached nearer to one than other.

Probably no two species wd have approached— I think Waterhouse views must be restricted to two distant groups.— for by my theory if every fossil were found, there wd be a blending between all forms, but not direct between two groups, which implies immense extinction

The Lepidosiren agrees in some points with Osseus & Plagiostomus

― differs ― from both is intermediate ― between. both