The animals of the class we are next to consider, have been regarded by many modern zoologists, especially of the French school, as inferior both to Crustaceans and Arachnidans, on account of their having only, as it were, a rudimental heart, exhibiting indeed a kind of systole and diastole, but unaccompanied by any system of vessels by which the blood might circulate in them. A learned and acute writer, and eminent zoologist, amongst our own countrymen, has with great force controverted the justice of this sentence of degradation pronounced upon Insects; an opinion which has also been embraced by many other modern writers on the subject, and considerable doubt has been shown to rest upon the main foundations upon which the illustrious and lamented Baron Cuvier, who was the father of the hypothesis, had built it.

But the important discoveries of Dr. Carus, who first proved that a circulation really exists in various larves of Insects, and afterwards that it is also discoverable in several perfect ones, have placed the matter beyond all doubt.