REGADKELLA. 221 



To give the differential character of eacli species in the form 

 of a key : 



«• — P:>rietal lejge only indicated. With onychasler (no oxyhexaster or oxystauraster). Large 

 oxypentactin parencliynialia present along the superior rim oftlie lateral wall. Prickly 

 parenchymal oxyhexactins not present, 

 a'. With true sieve-plate. Cufl' rudimentary. AVilhnut protal needles in tufts on the 



lateral wall iJ. ihcenij: O. Scum. 



!>'. Sieve-plate represented by a spicular wreatli ('corona) guarding the superior terminal 

 oseulum. Cud' well develojicd. With long prostal needles in tufts on the lateral 



wall ij. komeyamai Ij. 



'' — Parietali ledge conspicuously developed. Without large oxypentactin parencliymalia along 

 the superior rim of the lateral wall. With oxyhexaster, predominantly in the form of 

 oxystauraster. Numerous small prickly oxyhexactius present in the parenchymalia. 

 (True sieve-plate present, surrounded by a well developed cuff. Without tufls of prostal 

 needles) iJ. oklnoscana Ij. 



The idea of removing li. olcinoseana altogether from tlie 

 genus has often suggested itself to my mind. In fact I think 

 this step might be taken with some practical advantage to the 

 systematic. The presence of oxyhexasters and oxystaurasters 

 instead of onychasters, and also of small, prickly or spinose, 

 parenchymal oxyhexactins in large numbers, keep this species 

 somewhat apart from the other two, which mter se show an 

 essential agreement in spiculation. Another not unimportant dis- 

 tinction from those species seems to lie in the fact that in it 

 the large oxypentactin parenchymalia, which in R. pJioenix give 

 a strong support to the sieve-plate and in R. Icomeyamal supply 

 the coronal rays, are wanting. Perhaps it may not be altogether 

 inappropriate to associate R. olcinoseana generically with Corbiklla 

 speciosa { — Habrodiclyuvi speciosum Qx!OY &G aim a'rd), whicli, to 

 judge from W. Thomson's ('68) statements, seems to agree in a 

 measure with that species, amongst other points in being in 

 possession of oxyhexasters and evidently also of small smooth- 

 rayed hexactins which may correspond to the spinose parenchy- 

 mal oxyhexactin of R. olcinoseana. Howver, in view of uncertain- 



