18G ART. 7. 1. IJIMA : HEXACTINELLIDA, IV. 



parenchymal coraitaliii. The diactins run sometimes singly but 

 more usually a few are combined into thin bundles. 



The Jiypogastral diactins, likewise running singly or in loose 

 strands (see PI. XIII , fig. 11), are similar to the hypodermal. 



The oxypentacilnic hypodermalia (to be seen in PI. XIII., fig. 

 12) are large spicules with smooth, nearly straight or slightly bent 

 rays. The paratangentials are in most cases more or less distinctly 

 paratropal, but sometimes regularly cruciate. TJieir length meas- 

 ures 7-12 mm. and their thickness at base, about 100/^. The 

 unpaired proximal ray is longer ; it is accompanied l)y numerous 

 thin comitalia (about 9/^- thick) of the usual character. 



In the second specimen I find the hypodermal (and also the 

 prostal) oxypentactins somewhat smaller, the paratangentials meas- 

 uring mostly between 5 and 6 mm. in length. Nevertheless it 

 may be said that the spicule iu question is on the whole con- 

 siderably larger iu the present species than in either S. dowlinyi 

 or S. tubulosus. Decidedly larger does it seem to be tlian in the 

 former species, in which the paratangentials are said not to exceed 

 2.2 mm. in length. — The paratangentials of those pentactins already 

 protruded as prostalia remain smooth in most cases. Only occasional- 

 ly have I met with such prostal pentactins as have slightly rough or 

 granular paratangentials. The roughness is here due to the pre- 

 sence of rounded and iuconspicuous microtubercles somewhat like 

 those in S. doidingi but unlike the same in S. tubulosus. 



The dermalia (PI. XIII., fig. 3) are nearly exclusively 

 pentactins ; rarely and exceptionally, stauractins. The paratan- 

 gentials are neaily straight or very slightly arched. All the rays 

 are rough throughout ; they generally taper perceptibly outwards 



