138 Dr. J. E. Gray on Euplectella speciosa. 



l)liocene and miocene Tertiary epochs that we must seek for it. 

 Independently of the Cyprinoidei which are chiefly characteristic 

 of the fresh waters of our hemisphere, we find, in the gypseous 

 beds of Montmartre, in the marls of Puy-en-Velay, in those of 

 the Limogne d^Auvergne, and elsewhere, Cyprinodons (which 

 have also received the generic name of Lehias) which have no- 

 where been observed in beds of marine origin. 



XXV. — Additional Notes on Euplectella speciosa. 

 By Dr. J. E. Gray, F.R.S., V.P.Z.S. &c. 



The great interest which the importation of more specimens of 

 Venus^s Flower-basket {Euplectella speciosa) has excited induces 

 me to send you some further observations on this beautiful 

 Sponge. 



All the forty-eight or fifty specimens of the Euplectella that 

 I have seen are bent on one side, as in Professor Owen^s figure 

 of E. aspergillum ', there is one short, stouter specimen, which 

 came with the others from Zebu, that is nearly erect, which 

 induces me to believe that probably the E. cucumer of Owen is 

 only a shorter, broader, and erect specimen of the same species. 



Probably this curved form arises from the sponge growing on the 

 perpendicular face of the cliffs in the sea ; but all the specimens 

 which I have been able to examine seem to have been attached 

 to earth intermixed with fragments of shells, corals, &c., indi- 

 cating that they most probably live on mud-banks. 



It has occurred to me that this form may be produced by the 

 crab that inhabits them. From several indications in the dif- 

 ferent specimens, there can be no doubt that the sponge when 

 growing in the sea is rather more flexible than in the dry 

 state in which we receive it. The crab, which is of consider- 

 able size, the thorax being about an inch and a half wide and 

 an inch long when the tail is contracted, must enter the cavity 

 of the sponge while it is growing, when it is more flexible, and 

 before the netted lid is placed on the end of the central cavity, 

 and probably when the crab itself is of a smaller size. As the 

 crab becomes imprisoned in the cavity, it will be constantly 

 walking up and down the tube, to procure food; and by so doing 

 it will most likely bend the tube on one side, so that the free 

 end of the tube may become bent down nearly to the level of 

 the base. Most of the specimens which are brought to this 

 country have been more or less cleaned and bleached; but there 

 are two or three in the British Museum which appear to be in 

 their natural state ; and these seem to be more covered with the 

 external layer of short spicules on the convex side of the curve, 

 which would be the upper side of the sponge if it grows in this 



