12 August 2014

Tuesday Crustie: Victorian

I love old Victorian artwork, and this larval crab is no exception. This particular one is from a book by that brilliant but harsh anatomist Richard Owen, from a book titled, Lectures on the comparative anatomy and physiology of the invertebrate animals : delivered at the Royal College of Surgeons. The caption reads in part:

Larva of Crab. Second stage. Larva of Crab. First stage. they are then about half a line in length. Soon after exclusion this larva casts off its envelope and assumes the appearance represented in Jig. 139., which closely corresponds with that zoeaeiform Crustacean whose further changes were witnessed by Thompson, and which he had assured himself was an early or larval state of a common crab.The last form which immediately precedes the assumption of the mature characters corresponds, according to Thompson, with that of the genus Megalopa. The additional evidence adduced, in 1839, by Capt. Du Cane in proof of the actual metamorphosis of the Crustacean in question, was most acceptable. He affirms a corresponding metamorphosis to occur in the ditch-prawn (Palemon variabilis) and common shrimp (Crangon vulgaris). Dr. Thompson has witnessed similar metamorphoses in the genera Palinurus, Squilla, Pagurus, Porcellana, Galatea, and the marine species of Astacus, as well as in Palemon and Crangon.

Photo by Internet Archive Book Image on Flickr; used under a Creative Commons license.

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