Genera Pseudopygaulus, Trachy aster, and Ditremaster. 329 



of MM. CotteaUj Peron, and Gauthier^ and therefore it ought 

 to be abandoned together with Petalaster^ because they have 

 dates later than Eolampas. 



EOLAMPAS, Duncan & Sladen {op. cit. p. 61), 1882. 



Syn. Pefalaster, Cotteau, 1884. 



Psetidopygaulus, named by Coquand in ' Atlas,' 1862, published 

 Cott., Peron, et Gauthier, 1885. 



The species we published will therefore remain as we 

 printed them, without our names in brackets and without the 

 addition of the honoured name of M. Cotteau, who had 

 nothing whatever to do with their description. The other 

 species will be named Eolampas Toucasi, Cott. sp., E. Trigeri^ 

 Coquand sp., E. buccah's, Peron et Gauthier sp., and E. 

 GautMeri, Cott. sp. The terms Pseudopygaulus and Pefal- 

 aster are of necessity extinct. 



II. 



M. Cotteau has changed the generic position of Hemiaster 

 Brandertamcs, Forbes, //. p7'tnceps, Bittner, H. Archiaci^ de 

 Loriol, and H. decipiens^ H. apicalis^ H. nohilis^ and H. cari- 

 natus, Duncan & Sladen, from Sind. All these species now 

 stand in the genus Trachyaster ^ Pomel, and the names of the 

 original describers are placed in brackets and the name of 

 M. Cotteau follows. Two other species are also noticed. In 

 the Pal. Franq. :^ch. 1887, p. 400, it will be found that the 

 following is the synonymy given : — 



Trachy ASTER, Pomcl, 1883. 



Syn. Hemiaster^ pars, Desor, 1847, 1858. 

 Periaster, pars, Desor, 1868. 



M. Cotteau gives no other references, but remarks that 

 Tracliyaster is distinguished from Hemiaster of the Creta- 

 ceous epoch' by the madreporite separating the posterior genital 

 plates and the posterior ocular plates, and that it has four 

 genital pores. 



In the " Note sur la famille des Brissidees," Bull, de la 

 Soc. Zool. de France, 1887, vol. xii. p. 561, M. Cotteau gives 

 a short diagnosis of Tracliyaster^ but he does not men- 

 tion as a type any one of the species noticed by M. Pomel in 

 the work where the genus was first diagnosed. We are not 

 informed how Periaster, Desor, is connected with Ti^achyaster ; 



