CO Indian Gasteropoda. [No. 2, 



Observations on certain strictures by Mr. H. F. Blanford, on my 



Paper on the distribution of Indian Gasteropoda in J. A. S., No. 



CCLXXXIX. Page 69.— By W. Theobald, Jr. 



(Received 21st May, 1864.) (Read 1st June, 1865.) 



My friend Mr. Blanford, loc. cit., after reading the above paper, 

 among other remarks, expresses himself as follows : — " The sporadic 

 origin of species is not held by any eminent naturalist of the present 

 day, and Mr. Theobald had advanced no instance in its favour." 



Now the peculiar distribution of a few species over an enormous 

 area, was the reason for my preferring the supposition of a sporadic 

 origin for them at least as the only intelligible one, and if for the 

 majority of species, this view is not so imperatively recpvisite, yet for 

 aucb species as BvMmus pulhis, B. punctatus, B. gracilis, B. coenopictus, 

 and others, it naturally suggests itself, though I doubtless must have 

 expressed myself so badly as to warrant Mr. Blanford in denying my 

 having " advanced any instance in its favour." Rejecting however, 

 the obvious view, as I hold it to be, of sporadic origin, it yet remains 

 to be Been what explanation consonant with the Darwinian hypothesis, 

 can be offered, and I shall eagerly listen to Mr. Blanford's suggestions 

 on this point. 



I see of course, that in terming the origin of any species " sporadic," 

 I explain nothing, and that it amounts to a confession of ignorance, 

 still this is a negative evil and leaves the ground clear for any 

 superstructure winch fresh light may enable us to add, but not so a 

 positive assertion of a law, which, however, applicable in some cases 

 and true to some extent, does not meet all, and appears contradicted 

 by some. I will now advert to the first portion of Mr. Blanford's 

 stricture to the effect that I held views which no eminent naturalist 

 did. and certainly such a statement was not encouraging, but on 

 returning to station within the last month, I accidentally came 

 across a work which considerably reassured me ; though how far 

 Mr. Blanford will admit the names of A. A. G-ould and Louis 

 Agassiz to be eminent in their department, after the quotation 

 I shall presently make, I cannot say. Any how I find in the 

 " Principles of Zoology" by those Professors, my identical theory 



