KUNGL. SV. VET. AKADEMIENS HAKDLINGAR. BAND 58. N:0 9. 15 



guishing characters in view of tlie fact that this species is otherwise very variable 

 in outhiie (granting that the authors are right in uniting into one species both Lesu- 

 euri, elongatum Ag. and roslratum Ag. — I have not critically examined these forms 

 myself). Other distinguishing characters are not pointed out bj' Clark. It also 

 appears that a main reason for the establishing of a new species on this form was 

 the fact that P. Lesueuri had till then not been found on the West Australian coast. 



On one of the specimens was found a Polynoid * among the spines near the 

 periproct. 



To this species I refer provisionally a small specimen 25 mm long, from 45 

 miles W.S.VV. of Cape Jaubert, 47 m. (i2/VII. 1811) (PL IV, Fig. 12). It differs 

 from the typical form in having the edge of the test somewhat thickened, the 

 petals wider within and very distinctly narrowed at their outer end. The colour is 

 redbrown. It is stated to have been redbrown with a greenish tint, when alive. 

 Numerous ophicephalous pedicellariae are found on this specimen, but not one 

 tridentate pedicellaria of the peculiar form occurring in the large, typical specimens 

 could be found. The triphyllous pedicellariae have the blade slighth^ less widened 

 than is the case in the typical form. The spines do not present marked differences 

 from those of the typical form. 



A naked test (the apical system and genital pores lacking) from nearly the 

 same locality (48 miles W.S.W. of Cape Jaubert, 26 meters, 15/VII 1911) apparently 

 belong to this same variety, only the petals being still a little wider. 



It is quite probable that this form will ultimately prove to represent a distinct 

 species. With the material available it is, however, impossible to come to a definite 

 conclusion. Upon the whole I would say that I am by no means convinced that 

 all the different forms referred to P. Lesueuri by De Meijere really are only one 

 species. But a very large material will be necessary for deciding the question. 



10. Peronella orbicularis (Leske). 



LcKjauinn orhiciilarc. L. Agassiz. 1841. Moiiogr. de,s Kcliiuoilermes vivans et fossiles. II. Des Scutelles, 



p. 120, Tab. 22, Fig. 16—20. 

 » » De Meijere. 1904. Siboga-Echinoidea, p. 12r., Taf. YI, Fig. 09, 73—75, Taf. 



XVIII, Fig. 335 — .S39. 

 PcroiicUa orhicuJaris. H. L. Clark. 1914. IIa\Yaiian a. o. Pacific Echini. The Clypeastridae p. 52. 



To this species I refer provisionally two specimens from 45 miles W.S.W. of 

 Cape Jaubert, 18—20 m. (10-16/VII. 1911). 



They differ from the tyjiical form, as described by De Meijere, in the miliary 

 spines being not oblique. Only triphyllous and ophicephalous pedicellariae are found. 



A pair of naked tests from the same locality appear to belong to the same 

 species. 



* Mr. II.T. DiTLEVSEN- itifomis me that it is ai)]iarently a Gaslrolepklia, so far as can bo seen by a 

 quite cursory examination. 



