Debate between Cuvier and Geoffroy Saint-Hilaire

On the 15th of February, 1830, Geoffroy Saint-Hilaire read before the Académie des Sciences of Paris (under Latreille’s name as well as his own) a report on the works of two young naturalists, Laurencet and Meyranx, who had set out to demonstrate that the physiological organization of cephalopod molluscs1 could be related to that of the vertebrates. In 1823, Latreille had taken a special interest in this subject and had pointed out several types of external resemblances between squid and fish. De Blainville had also attempted to make comparisons of this kind. Laurencet and Meyranx delved more deeply into the question and tried to find connections between the various organs of a cephalopod similar to those seen in vertebrates. To do that, they had to resort to an ingenious fiction. They assumed a vertebrate that was doubled over at the level of its navel, so that the face of the ventral side remained outside and the two halves of the back were welded together. The pelvis was close to the neck, and the limbs were attached to an extremity of the body, so that when the animal was walking on these limbs it took ‘exactly the same position as an acrobat who turns his head back over his shoulders and hands.’ The intestines of the cephalopods are doubled over, pieces of cartilage in the rear of their neck are connected to what is called their funnel, and eight or ten limbs around the head serve as arms and legs. These features are so characteristic that they offer a natural explanation and an unexpected way to place the most elevated of the molluscs at the level of vertebrates. The parrot-like beak of the cuttle-fish and its large, complex eyes serve to make these analogies even more convincing.