272 ART. 7. — I. IJIMA : HEXACÏINELLIDA, IV. 



Spiculation. 



The following account is based on my observations on the 

 type specimen, except when other specimens are specially referred 

 to. 



The principal parcnchymcdia are large oxydiactins which may 

 measure 30 mm. in length and 175 p- in breadth in the middle. 

 They are generally more or less bent and gradually attenuated 

 towards both ends, which are rough for a short distance even in 

 the largest of the spicules. The accessory parenchymalia present 

 no point that seems to require special mention. 



The prostal oxydiacti7is of the marginal zone may attain a 

 length of 25 mm. and a breadth of 85 /z in the middle. They are 

 smooth throughout, without any indication of the spiny character 

 of the distal parts, such as has been observed in H. mirabilis. 



The prostal oxypentactins have paratangentials which are 

 nearly always paratropal and are 8-11 mm. long and about 85/^ 

 broad near the base. The spines on the paratangentials may be 

 as high as 150 /a Basally on the rays they are rather irregularly 

 disposed but more distally are arranged in two lateral rows. The 

 smooth shaft-ray generally measures 15 mm. or over in length. 

 On the basal mass of the sponge it may be as long as 40 mm. 



With respect to the arrangement of the same oxypentactins 

 as hypocJe7'malia and of the younger spineless hypodermal oxy- 

 pentactins, what I have said under R. victor may be considered 

 to apply equally well to the present species. 



