38 ART. 1.— i. IJIMA : HEXACTINELtlDA, III. 



Tlie gaüralia differ in no way from the ordinary parenchymal 

 oxyhexactins in their characters, except in being on the whole 

 smaller and in having proportionally thinner rays. Axial length 

 1^80,« and over. It would not he improper to say that they are 

 here represented simply by those parenchymal oxyhexactins which, 

 being situated in the deepest part of the wall, project one 

 of their rays into the gastral space. They are found rather 

 irreo-ularly scattered and are far from forming a continuous 

 gastral layer. 



Like the gastralia the dermalia are only slightly dilïerentiated 

 from the parenchymal hexactins, except in lacking a distally 

 directed, sixth ray. To be more explicit, the dermalia are 

 exclusively moderately large oxypentactins with the rays supplied 

 with sparsely distributed, quite insignificant microtubercles similarly 

 as in parenchymal oxyhexactins. The cruciate paratangentials 

 up to 270 /'- in length and 15 /^- in Ijreadth near the central 

 node, are in either a perfectly flat or a slightly outwardly curved 

 plane. The straight, unpaired, proximal ray is longer than, — 

 often fully twice as long as, — the jiaratangential in the same 

 spicule ; it generally runs in association with a radially directed 

 beam of the parenchymal framework. Observed from the surface, 

 the centers of the paratangential crosses lie separated from one 

 another by a space nearly equal to, or considerably less than, 

 the length of the paratangentials, — by a distance of about 200/-« 

 on an average. Occasionally there are seen two centers, placed 

 close together. At the same time the paratangentials form the 

 usual, quadrate-meshed, dermal latticework, the beams of which 

 are composed usually of two, but sometimes of one or three, 

 rays running together. As is usual, the dermal meshwork is 



