ORTMANN I TERTIARY INVERTEBRATES. 53 



Remarks: Our single specimen is very badly crushed on the under side, 

 but fortunately there are preserved a number of spines : these are short, 

 thin and sharply acuminate, with fine longitudinal striations. The form 

 of the actinostome is unknown. 



Hyp. patagonicus (sic!) mentioned by v. Ihering (1897 a > P- 33^) appar- 

 ently does not belong to this species, since he says that individuals from 

 the Bay of San Jorge in his possession differ in the number of tubercles in 

 the interambulacra. Possibly they belong to the next species. 



Record of specimens : San Julian, Darwin Station, i sp. 



Distribution : l So far only known from San Julian (d'Orb.). 



Affinities: The chief character of this genus is found (according to 

 Desor) in the primary tubercles of the ambulacra, which are, on the actinal 

 side, about as large as those of the interambulacra, but decrease rapidly in 

 size toward the abactinal system, becoming much smaller than the latter. 

 Although this character does not seem to warrant the generic separation 

 of this species from Echinus, it is not observed in any other species, and 

 so it is impossible to point out any particular relations to any known spe- 

 cies of Echinus. 



Gen. TOXOPNEUSTES Ag. 

 3. TOXOPNEUSTES PR/ECURSOR Ortmann. 



PI. XI, Fig. 3 . . 



? 1897 Hypechinus patagonicus v. Ihering, in: Rev. Mus. Paul., v. 2, p. 



336 (non H. patagonensis d'Orb.). 

 1900 Toxopnetistes prtectirsor Ortmann, in: Amer. Journ. Sci., v. 10, p. 



369- 



Test suborbicular, slightly subpentagonal, subconical. Ambulacral and 

 interambulacral spaces with 4-8 vertical rows of tubercles, of subequal 

 size, those of the ambulacral spaces being a little smaller. Poriferous zone 

 moderately broad, about half as broad as the median part of the ambu- 

 lacrum. The latter with 4 vertical rows of tubercles, the two outermost 

 the largest, and only these extending to the abactinal system. Pores in 

 three pairs, the two outer vertical rows of pores placed slightly closer 

 together, and separated from the inner row by a small tubercle, these 



1 Under this head I shall give the data of distribution previously reported. 



