Immediately the young are set free, they must instinctively bury the ends of their forceps in the hardened egg-glue which is smeared over the swimmerets, for they are all found to be holding on in this manner. They exhibit very little movement, and they bear rough shaking or handling without becoming detached; in consequence, I suppose, of the interlocking of the hooked ends of the chelæ imbedded in the egg-glue. Even after the female has been plunged into alcohol, the young remain attached. I have had a female, with young affixed in this manner, under observation for five {44} days, but none of them showed any signs of detaching themselves; and I am inclined to think that they are set free only at the first moult. After this, it would appear that the adhesion to the parent is only temporary. The walking legs are also hooked at their extremities, but they play a less important part in fixing the young to the parent, and seem to be always capable of loosing their hold. I find the young of a Mexican crayfish (_Cambarus_) to be attached in the same manner as those of the English crayfish; but, according to Mr. Wood-Mason’s recent observations, the young of the New Zealand crayfishes fix themselves to the swimmerets of the parent by the hooked ends of their hinder ambulatory limbs. * * * * * Crayfishes, in every respect similar to those found in our English rivers, that is to say, of the species _Astacus fluviatilis_, are met with in Ireland, and on the Continent, as far south as Italy and northern Greece; as far east as western Russia; and as far north as the shores of the Baltic. They are not known to occur in Scotland; in Spain, except about Barcelona, they are either rare, or have remained unnoticed. There is, at present, no proof of the occurrence of _Astacus fluviatilis_ in the fossil state. * * * * *