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In the spring of the following year, 1869, the Lords Commissioners of the Admiralty despatched the surveying vessel ‘Porcupine’ to carry on the work commenced by the ‘Lightning.’

The first cruise was on the west coast of Ireland, the second cruise to the Bay of Biscay, where dredging was satisfactorily carried on to a depth of 2,435 fathoms, and the third in the Channel between Faeroe and Scotland.

The dredging in 2,435 fathoms was quite successful, and the dredge contained several Mollusca, including new species of Dentalium, Pecten, Dacrydium, &c., numerous Crustacea and a few Annelids and Gephyrea, besides Echinoderma and Protozoa. A satisfactory dredging was also made in 1,207 fathoms.

The third cruise was also successful and brought many new species to light, including the Porocidaris purpurata, and a remarkable heart urchin, Pourtalesia Jeffreysi.

Concerning Pourtalesia Sir Wyville Thomson says:—

‘The remarkable point is that, while we had so far as we were aware no living representative of this peculiar arrangement of what is called “disjunct” ambulacra, we have long been acquainted with a fossil family—the Dysasteridæ—possessing this character. Many species of the genera Dysaster, Collyrites, &c., are found from the lower oolite to the white chalk, but there the family had previously been supposed to have become extinct.’