7f) FOSSIL ECHINI FROM THE TERTIARY 



height zn 17 mm. 



diameter of basis = 24 mm. 



» » abactinal system =: 6 mm. 



» » actinal system = 8 mm. 



This fossil is so entirely different from the only recent 

 representative of this interesting genus , P. hothryoïdes Ag. 

 (from the Indian Ocean) , that an enumeration of the spe- 

 cific diff'erences may appear superfluous. On the other 

 hand Temnopleiirus tuherculosus , a PleurecMnus from the 

 tertiary strata of India, which was described under that 

 name by d'Archiac and Haime, is very nearly related to 

 our Javanese form. However in this Indian fossil the 

 number of the vertical ridges , which connect the widest 

 plates of the interaiubulacral areas , is less , the rows of 

 primary tubercles do not occupy the middle of these plates, 

 whereas the number of smaller tubercles is at the same time 

 diminished. 



4. Stomopneustes variolaris Ag. It is impossible 

 to distinguish Heliocidaris variolosa Herhl. (1. c. pag 5 , 

 tab. I , fig. 4) from this species , although Herklots pre- 

 tends, that the Javanese fossil differs: »par les rangées se- 

 condaires de gros tubercules sur les aires ambulacraires 

 moius développées et par la forme conique a base parfaite- 

 meut plane." A comparison of a series of recent specimens 

 from this species , which is so common in the Indian Ocean 

 and on the coast of Java , shows , that there is a considerable 

 range, between which this species may vary , not only with 

 respect to the development of the tubercles but especially to 

 the form of the test. The basis is flattened in a varying degree , 

 and I feel obliged to identify this fossil, however strong it 

 may be flattened, with S. variolaris Ag. The axis of the 

 test has the same obliquity as in the recent specimens. 



5. l/aganutn tnultifortne nor. spec. The outline 

 of the test is very variable , distinctly pentagonal with 

 rounded angles or even nearly elliptical with hardly any 

 reminescence of the polygonal form. The greatest dia- 

 meter is in a line with the anterior extremities of the an- 



Notes from the Leyden TVXuseum, AT'ol. II. 



