EHABDOCALYPTUS VICTOR. 243 



patterns, — that they converge towards numerous central points, 

 lying 3-7 mm. apart from one another. At each of these is situated 

 the papilla-like prominence mentioned above. The radial pattern 

 is caused by the paratangentials of a number of hypodermal 

 pentactins which are arranged in a group (PL XVIII., fig. 16), 

 their shafts and the accompanying comitalia combining together 

 to form a loose, vertically dipping bundle. The axis of this 

 bundle is occupied by the erstwhile comitalia to the shafts of 

 prostal pentactins which were once present at the spot but are 

 now lost. The outer ends of the comital spicules in question form 

 a compact bundle and, projecting more or less beyond the dermal 

 surface, give rise to the small papilla-like prominence at the 

 center of each radial figure brought about by the hypodermal 

 strands. In the inferior region of the body, the prominences are 

 generally disintegrated and take tlie form of little parallel tuft 

 of fine spicules, projecting to a length of 2 mm. or less (PI. XIX., 

 fig. 23) ; whereas, in the superior parts they are usually to be 

 seen as whitish, slightly elevated spots. The prostal pentactins, 

 when present, invariably stand out on the papilla-like prominences, 

 either singly or a few together in a tuft. 



However, prostal pentactins are in general Ijut sparsely present 

 in the mature specimens : they seem to become readily lost as 

 they are somehow shed ofi". Many individuals are quite or nearly 

 destitute of the prostalia in question, showing at most only a few 

 isolated representatives of them. But under certain circumstances 

 they may be somewhat extensively preserved not only in such 

 parts as seem to be protected in a way from abrading influences 

 but also on the exposed lateral surfaces. The spiny armature of 

 the prostal paratangentials can be easily recognized when seen 

 under the hand-lense. Diactinic prostalia, apart from those which 



