CRIBRILINA RADIATA. 187 



Var. y (ttimii-tHttris} . \V itli the aviculariura developed on a 

 distinct crll ; inaudible short, broad at the base, much 

 attenuated above. 



RANGE OF VARIATION. After careful consideration I have 

 uu it i'd the Eschara radiata, Moll, and the Lepralia inno- 

 ii/i/ntla, Johnston, as one species. The chief difference 

 between them is that one of them has the large pore 

 below the orifice, and the other wants it ; but this is far 

 from being a constant distinction between these two forms, 

 and cannot be used in this case as a specific criterion. 

 It must be remembered that specimens which exhibit 

 most strikingly the differences between the radiata and 

 innominata types are connected at all points by very 

 numerous intermediate and transitional forms, in which 

 the elements of the two are variously mingled and com- 

 bined. In a specimen before me, presenting the general 

 characteristics of radiata, the triangular area below the ori- 

 fice is present, but not perforated. The Lepralia pretiosa, 

 Reuss, which is referable to the same type, is furnished 

 with the median pore. In Lepralia raricostata, Reuss, 

 a very well-marked example of the innominata type, the 

 pore is wanting. In the Lepralia Endlicheri, Reuss, 

 which I am inclined to refer to the same series, the pore 

 is present on some cells and absent on others. The 

 form from Madeira, which Busk figures (Quart. Jouru. 

 Micr. Sc. vi. pp. 128 & 263, pi. xx. fig. 4) as L. radiata, 

 and which undoubtedly exhibits many of the characteris- 

 tics of Moll's species, has the median pore well developed ! 

 The L. innominata of Manzoni from the Mediterranean 

 seems to be somewhat intermediate between the two 

 varieties ; it wants the median pore. In other respects the 

 two forms pass insensibly one into the other. The differ- 

 ences, too, which lie chiefly in trxtuiv, the more or less 



