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March 31. /44/ I suspect that typical implies having many species

Swainson's statement (& Waterhouse independently to me) that typical genera (which implies with respect to larger group) (for Ornithorhynchus can only be considered non-typical with respect to mammifers) have wide ranges (⸮ converse may still hold good?) is important; for the genera which are not typical are only rendered so by the extinction of allied genera, & that implies they are less adapted than other groups of genera to the their world & their co-inhabitants — & therefore one might expect they wd be less widely distributed: they (as genera) wd be rare, for they have or are decreasing in number — like individual species.—

(good) Mem. Westwoods contradiction in Linn: Trans:—

In another sense Balanus Octomeris aberrant

Octomeris type of Sessile — Pollicipes of Thoracica whole order

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v. Hooker's letter on what Typical means. I do not doubt it only refers to extinction or rather fewness of forms.= Hookers statement makes fewness of osculant groups a truism.—

Linn. Trans. vol 18 p. 417.1 it is very curious that "so aberrant a form" (Silphomorpha &c. & 4 carabideous peculiar genera) "should be found in regions so distant in N. America, Brazil & N. S. Wales. This fact alone I shd imagine must be considered sufficient to prove that a wide geographical range is not the character of a typical group. as stated by Mr Swainson."

(it rather proves converse ie. that some non-typical groups have wide ranges.—)