256 BULLETIN OF THE 



young are usually enveloped, has been entirely cast off, and the lateral spines 

 and the rostrum are fully expanded, and the second zoea-stage about to be 

 described." * 



As I have now shown that the first stage is really devoid of lateral spines, 

 and has only a short and broad rostrum, it is to be inferred that the so-called 

 " second zoea-stage '' (which was taken in the towing-net) is in reality a later 

 one in the development.t I was unable, mth the greatest care, to rear any 

 larvae through the first moult into the second stage, but I think that one if not 

 more stages remain to be discovered between the first and the earliest described 

 by Smith. 



II. Porcellana (Polyonyx) macrocheles. 



Among the interesting Crustacean larva? which the Gulf Stream bears to the 

 southern shores of New England from more southern latitudes, is the peculiar 

 zoea of Porcellana macrocheles. Not uncommon on the coast of the Carolinas, 

 the adult has been found but once, as far as I know, on the coast of New Eng- 

 land, Mr. Alexander Agassiz having detected it under stones on the shore at 

 Newport, R, I. In the same category are the young of Calappa marmorata and 

 Ocypoda arenaria, which are found, the former rarely, the latter quite com- 

 monly, as far north as Cape Cod, but which rarely, if ever, survive our rigorous 

 winter.^; 



* Op. cit., pp. 314, 315. 



t Professor Smith's "numerous attempts to obtain newly hatched young, by keep- 

 ing egg-carrying females in aquaria, failed from the parent's invariably casting off the 

 eggs before they were fully matured." (jOp. cit., p. 314.) By selecting females with 

 eggs considerably advanced toward maturity, and placing them in a cool place, in 

 shallow vessels covered at the bottom with clean sand, iind renewmg the water twice 

 a day directly from the sea, I found no difficulty in obtaining several broods of young 

 at various times between the 1st and 30tli of August. I succeeded best by covering 

 the sand with but a slight depth of water, and tipping up the vessel a little so that 

 part of the sand was above water, thus imitating the natural beach, where at low 

 tide the Hippm are found in the wet sand just above the water- mark. I observed 

 that in vessels so placed the Hippce for a large part of the time preferred the wet sand 

 above the water-line. 



For the free use of the laboratory and apparatus of the United States Fish Commis- 

 sion at Wood's Hole, in the summer of 1877, I am indebted to Professor S. F. Baird, 

 U. S. Commissioner of Fish and Fisheries. 



t Professor S. I. Smith found small, young specimens of Ocypoda arenaria in the 

 latter part of August and in September on Fire Island Beach, Long Island, but care- 

 ful search failed to reveal a single specimen of the adult or half-grown crab. (Amer. 

 Jour. Sci. and Arts, 3d Series, VI. p. 68. 1873. Invert. Animnls of Vineyard 

 Sound, p. 241. 1873.) No one has found the zoea of this animal so far north, 

 although the megalopa is not uncommon. The zociB of Porcellana which I collected 

 at Newport were nearly all in the last stage of their development. From these facts 

 it is higldy probable that these species are not natives of the New England coast. 



