Zoological Illustrations Series II/Plate 29



This is a genus of fresh water shells, particularly abundant in Africa, Asia, and America; we have also heard it has lately been detected in Europe.

We should not have figured this common and well known shell, but for the purpose of comparing it with the next. When in a young state, the spines are very acute: more advanced they become less so; and in old individuals they are often very obtuse.

This is a most singular species. From the tubular spines emerge two or three hornlike, elastic bristles, which appear embedded in the substance of the shell. A very ample account of the first specimen we ever met with, will be found in Brand's Journal for April, 1824. It was discovered in the Isle of France, by Mr. Warwick, where it appears to be very rare. Other specimens have since been brought to this country.

We were unwillingly drawn into a controversy respecting this shell some years ago. Our sentiments, in every thing that regards the shell itself, are unchanged. Not so with respect to the individual. The civilities and attentions we have since received from Mr. Gray, leave us to regret, very sincerely, that such a discussion should have ever taken place.