RHARDOCALYPTUS VICTOR. 247 



disposition ; hence, the paratropism. It may be said that in each 

 group the oklest pentactins are the most centrall}" situated ; thus, 

 after tlieir protrusion as prostalia hiteralia ; they stand out from 

 the center of a hypodermal group ; and when cast off, they leave 

 behind in tliat position a compact little l)uncli of the outer ends 

 of fine needles that accompanied their lost shafts as coraitalia. 



After full development, the hypodermalia have the paratan- 

 gentials armed from base to tip with strong and sharply pointed 

 prongs, arranged in two series along the lateral sides of the rays. 

 The prongs are situated at tolerably regular intervals, those of 

 the two sides alternating with one another. In the l)asal parts of 

 the rays, the strongest prongs may be 100 ," long ; there they all 

 spring out nearly vertically but soon become bent in a claw-like 

 manner, the bending taking place generally either backwards or 

 forwards, and occasionally downwards away from the dermal surface. 

 I do not remember ever to have seen the prongs bent upwards. 

 Towards the tip of the rays and along with the gradual attenu- 

 ation of these, the prongs grow continually smaller, and in the 

 terminal parts they are simply thorn-like, being directed obliquely 

 forwards. Apart from the above prongs, the surface of the 

 paratangentials is perfectly smooth. The unpaired shaft-ray is 

 never pronged ; it is entirely smooth except for a few microtubercles 

 which may be present near its inner pointed end. 



The prostal pentactiiis, i.e., the hypodermalia after protrusion 

 through the dermal layer, always show^ pronged paratangentials. 

 The protrusion evidently takes place only after complete develop- 

 ment of the armature, a fact which seems to hold true for all 

 members of the genus. The paratangentials are, as measured on 

 the prostalia, generally 5.5-6.5 mm. long and the shafts, 4.5-8 



