362 Mr. H. J. Carter on some West-Indian 



p. 83, I. c.) which comes nearest in form to tliat of Donatiaj 

 where the body is large and the spines short, is that of Chon- 

 drilJa nucula, while that of G. sacciformis, Carter, from 

 Mam'itius, in size and ligm*e is almost identical with it. 

 Moreover there is a great resemblance in structure and spicu- 

 lation between Donatia It/ncuriunt and Axos Cliftoni, wherein 

 the small flesh-spicule, viz. " no. 4 " in the former, is almost 

 identical in form with a similar one in the latter ; and tlie 

 globostellate of Donatia lyncurium only a modilication of the 

 sexradiate cross-like one with multifidly-spined rays in Axos 

 Cliftoni, as may be seen where the central part or body of the 

 latter is much enlarged. 



Family 3. Pacjiytragida. 



Group Geo DIN A. 

 Geodia tumulosa, Bk., Proc. Zool. Soc. 1872, p. 628, pi. xlvii. 



On an agglomeration of two large pebbles &c. a foot in dia- 

 meter, bearing two specimens of PoJytherses, Cliona carihha'a 

 in Porites, and four species of sessile stony corals, all of 

 considerable size, (the largest Polytherses^ which is conical, 

 being 5 inches high and tlie same in diameter at the base) , 

 together with a large piece of wood artificially scjuarecl and 

 somewhat eaten by marine animals, but by no means in a 

 state of decay, is a specimen of Geodia tumidosa, Bk., which 

 has grown over nearly one third of the mass, which was found 

 at Puerto Cabello, in the Caracas. Tlie specimen of Geodia 

 is well characterized in Dr. Bowerbank's representation of this 

 species, the localities for which are stated to be "Honduras and 

 Jamaica," and therefore requires no description of my own 

 beyond the above, which is given in detail, to show by the pre- 

 sent state of the tcood in the conglomerate with what rapidity 

 these marine animals grow and thus firmly cement together 

 such large detritus. 



There is another, small, thin specimen, about 2^ inches 

 square, that had also grown between stones at the island of 

 St. Vincent, and seems to be De F. et M.'s Geodia carihhcea^ 

 in which the surface-cliaracter is ditierent from that of the 

 foregoing specimen (apparently their G. gibber osa, ham.), but 

 which 1 shall presently endeavour to show is but a varia- 

 tion of G. tumulosa, Bk., and, finally, G. gibberosa, Lamarck. 



The spiculation is the same in both the specimens from 

 Puerto Cabello and St. Vincent : that is to say, the zone- 

 spicule in each consists of a long shaft, terminated by three 

 simple arms expanded laterally and a little advanced (PI. XII. 



