TEMNOPLEURUS. 311 



Opechinus variabilis Mrtsn. 



Pleurechinus variabilis Doderlein, 1885. Arch. f. Naturg., Jahrg. LI, 1, p. 93. 

 Opechinus variabilis Mortensen, 1904. Dan. Exp. Siam: Ech., p. 92, 94. 



Examination of the test of this species seems to confirm Mortensen's view 

 that its relationship is with Temnechinus rather than with Temnopleurus, for 

 there is no evidence of dowelling between the plates and they are rather thinner 

 than would be expected from the outer surface. Our specimens are small 

 (8-11 mm. in diameter) and the pits at the angles of the plates are often very 

 small or wanting while the large depressions on the sutures are very conspicuous. 



The "Albatross" took this species at the following stations: 



Station 4893. Southwest of Goto Islands, Japan; 32 32' N., 128 32' 50" E. 

 Bott. temp. 55.9. 95-106 fathoms. Gy. s., brk. sh., p. 



Station 4894. Southwest of Goto Islands, Japan; 32 33' N., 128 32' 10" E. 

 Bott. temp. ? 95 fathoms. Gy. s., brk. sh., p. 



Station 5068. Suruga Gulf, Japan; 35 2' 25" N., 138 46' 55" E. Bott. 

 temp. 63. 77-131 fathoms. Bk. s., brk. sh. 



Bathymetrical range, 77-131 fathoms. Extremes of temperature, 63- 

 55.9. 



Three specimens. 



TEMNOPLEURUS. 



L. Agassiz, 1841. Int. Mon. Scut., p. 7. 

 Type-species, Cidaris toreumalica Leske, 1778. Add. ad Klein, p. 155. 



This genus has been so recently and so fully revised by Mortensen that 

 only agreement with his general conclusions need be expressed. There seems 

 to be no reason to doubt that T. Reynaudi is really synonymous with toreumaticus 

 and therefore the species long known as Reynaudi must take Gray's name 

 Reevesii. The other species, Hardwickii, is near toreumaticus but with the spines 

 on, the two are very easily distinguished. All three species occur in Japanese 

 waters, but toreumaticus extends westward to Arabia and southward probably 

 to Queensland, while Reevesii ranges westward to Ceylon, and Hardwickii so 

 far as known, is peculiar to Japan, the record from Unalaska being exceedingly 

 dubious. 



The three species 1 may be distinguished from each other regardless of the 

 differences in the sculpturing of the test, which shows great individual diversity, 

 as follows: 



1 For Perezi, see below under toreumaticus. 



