14 TH. MORTENSEN, ECHINOIDEA. 



Although I have no small specimens of darnleyensis for comparison, I have 

 very little doubt that the present specimen really belongs to this species. At least 

 it is very closely related to this species, and from the material available no diffe- 

 rences can be pointed out. Tridentate pedicellariae are not found in this specimen. 



8. Heterocentrotus mamillatus (Klein). 



Heterocentrotus mamillatus. A. Agassiz. 1872 — 73. Revision of the Echini, }>. 13:;. 128. Pl. III. c, 



Pl. XXVI, Figs. 1-2, 14. Pl. XXVIII, Fig. 8. 

 De Loriol. 1883. Catalogue raisonnc des Échinod. rec. ... å 1'ile 

 Maurice. Mém. Soc. de phys. et d'hist. nat. de Geneve, XXVIII, p. 3f>. 

 » Tu. Mortensen. 1903. Ingolf-Echinoidea, I, p. 1 21). 



De Meijere. 1904. Siboga-Echinoidea, p. 102. 

 » II. L. Clark. 1912. Hawaii an a. o. Pacific Echini. The Pedinidae . . . 



and Echinometridae, p. 378, Pl. 115—117. 



One dried specimen, labelled Cape Jaubert. 



9. Peronella Lesueuri (Val.) 



Pl. V, Fig. 25. 



Laganum Lesueuri. L. Agassiz. 1S41. Monographie d'Echinod. vivans et fossiles. II. Des Scutelles. 



p. 116, Tab. 24. Fig. 3-6. 

 Peronella decagonalis. A. Agassiz. 1873. Revision of the Echini, p. 521, Pl. XIII. e, Figs. 8 — 10. 

 Laganum Lesueuri. De Meijere. 1904. Siboga-Echinoidea, p. 122, Taf. VI, Fig. 63, 67, 70, Taf. 



XVIII, Fig. 329—333. 

 Peronella » H. L. Clark. 1914. Hawaiian a. other Pacific Echini. The Clypeastridae . . . Mem. 



Mus. C. Zool. Vol. XLVI, p. 53, Pl. 124, Figs. 23—24. 

 Laganum Döperleix. 1914. Echinoidea; Fauna Siidwest Australiens, p. 490. 



Peronella aphnostina H. L. Clark. 1914. Echinoderms W. Austr. Museum, p. 167, Pl. XXIV. 



Two large specimens, 130 mm long, labelled only West Australia 1911. They 

 are of the typical shape, as figured in Tab. 24, fig. 3—4 in L. Agassiz' Monograph. 



Like H. L. Clark I do not find the component rods of the miliary spines 

 quite so abruptly widened as De Meijere figures them. Concerning the pedicellariae 

 I would remark that the larger tridentate form (Pl. V, Fig. 25) appears to me some- 

 what more slender than figured by H. L. Clark, and there is a rather long slit 

 downvvards from the outer widened part, while H. L. Clark figures the narrow 

 tubeformed part as closed up to where the widening begins. Ophicephalous pedicel- 

 lariae were not found. 



The Peronella aphnosti?ia of FE. L. Clark seems to me untenable as a separate 

 species. The differences in the shape of the test seem hardly sufficient for distin- 





1 The name Peronella is taken liere in the sense of II. L. Clark, öomprising the Laganids with 4 

 genital pores, those with 5 pores being refcrred to the genus Laganum. I would say, however, that 1 do not 

 fecl conviuced that this difference in the number of the genital pores corresponds to the natural relationship ot 

 the Laganid species. But it is practical and ni av be very conveniently used, until it has been proved that 

 it is artificial and thus witliout generic value. 



