14 ECHINODERMS OF THE CRAG. 



Spatangus purpuueus, Lamarck, Anim. sans Vert., 1st ed., vol. iii, p. 29; 2d ed., 

 vol. iii, p. 324. 



— — Fleming, Brit. Anim., p. 480. 



— — Blainville, Man. d'Actin., p. 202, pi. xiv, figs. 1—3. 



— — Forbes, Brit. Starf., p. 182, (with figure.) 



— — Agassiz and Desor, Ann. Sc. Nat., 3d ser., vol. viii, p. 6. 



— — Duben and Koren, Kong. Vet. Akad. Hand., 1844, p. 285. 

 Echinus purpureus, Gmelin, Lin., p. 3197. 



— lactjnosus, Pennant, Brit. Zool., iv, p. 69, pi. 35 and 76. 



Identical with this well-known living species, (of which Spatangus meridionalis of 

 Risso, and S. spinosissimus of Desor, appear to be varieties,) is one of which about half 

 the test is preserved, in the collection of Mr. Searles Wood, from the Coralline Crag of 

 Ramsholt. It differs from our ordinary British form in being slightly more carinate at the 

 sides of the anterior ambulacral sulcus, a character in which it approaches to the more 

 southern varieties, and at the same time agrees with ours in shape and degree of depression; 

 being, indeed, if anything, slightly more depressed. The antero-lateral ambulacra are 

 slightly narrower, the primary tubercles quite as numerous. The specimen is not in such 

 a state as to warrant a more minute description. 



2. Spatangus Regina? Plate II, fig. 2. 



Spatangus Regina, Gray, Ann. Nat. Hist., 2d ser., vol. vii, p. 130? 



In the collection of Mr. Brown, of Stanway, there is a large fragment of a true 

 Spatangus. It is the greater portion of the upper surface, from the margin of the vent to 

 the anterior extremity, which latter is unfortunately, however, concealed by adhering 

 matter. One of the postero-lateral, and part of one of the antero-lateral ambulacra, are 

 exposed. The postero-lateral ambulacrum is lanceolate, with a gently flexuous outline. 

 The two avenues converge suddenly. There are about 26 pairs of pores in each avenue. 

 Each pair is lodged in a deep and well-defined sulcus. The number of pairs of pores in 

 the antero-lateral ambulacra cannot be made out. The whole of the surface is closely set 

 with miliary granules. On the ambulacral spaces there are no primary tubercles, but 

 in the centre of the postero-lateral and posteal interambulacral spaces, the only ones 

 exposed, there are groups of nearly equal primary tubercles forming curved assemblages. 

 Between them, on the interambulacral spaces, there are curved depressions in the test. 

 The whole body seems to have been broad and depressed. It measured rather more than 

 four inches in length by rather less in breadth. 



Another fragment of a true Spatangus, also from the Coralline Crag, exhibiting the 

 cordate anterior extremity, the granulated groove of the anterior ambulacrum, tumid and 

 slightly angulated cheeks, and the portion of the anterior surface in front of the mouth, 

 may have belonged to another species, or to only a more tumid form of the same. 



