58 ART. 1. — T. TJIMA : HEXACTINELLIDA, III. 



usually wanting, thus directly exposing the thick, wavy, soft and 

 silky bundles of the parenchymalia. 



An unusually wide subdermal space separates the dermal 

 layer from the choanosorae (see PL IV., fig. 4). In the larger 

 specimens it may in places be nearly 10 mm. wide. Pillars of 

 conical or irregular shape project from the choanosomal surface 

 at intervals of 5-12 mm. or more ; these divide at the apex into 

 a number of fibrous bundles which go to join those of the 

 dermal layer. 



The oval or round entrances into the incurrent canals are 

 more or less conspicuously visible through the dermal layer. 

 They are on the whole very large, though by no means uniform 

 in this respect, either in the same specimen or in differently sized 

 individuals. In the specimen of fig. 1, PL IV., some of the 

 incurrent canalar openings have a width of 15 mm. or even more ; 

 in that shown in the woodcut on p. 54, the largest opening 

 measured 10 mm. across. 



In all large specimens there exists a continuous gastral layer, 

 covering up the wide apertures of the excurrent canals. This is 

 of nnich the same irregularly reticular appearance as the dermal 

 layer ; only it may be said that in general the meshss are 

 somewhat wider, while the intersecting points of the beams strike 

 the eye as small whitish knots due to accumulations of certain 

 discohexasters. In the interapertural spaces the layer lies closely 

 over, and is often indistinguishable from, the parenchymal tissues. 

 In the medium-sized specimen of fig. 10, PL V., the gastral layer 

 leaves a few of the excurrent apertures uncovered, seemingly not 

 as a result of artificial disturbance. In small specimens, such as 

 are depicted in figs. 8 and 9, PL V., all the excurrent canals 

 open directly into the gastral cavity. The gastral layer then 



