89 • 



wards the end of the ray like the branches of an ItaUan poplar towards the 

 top of the stem (pi. XV, f . 4). The tangential rays are simple, straight, slightly 

 tuberculous at the blunt ends and about as long as the distal ray. The proximal 

 ray is similar in shape but generally longer. 



The gastralia are stout, straight diactines with or without a more or less 

 clearly defined swelUng, or two or four rounded protuberances, or even rudiments 

 of a third and a fourth ray, in the middle. Their ends are rounded and 

 always covered more or less densely with small, pointed tubercles. Usually, 

 but not always, the spicule is covered with such protuberances in its entire 

 length. The length of these spicules varies considerably from about 1 to 2 mm. 

 and more. Not infrequently spicules of this kind slightly bent or terminally 

 thickened in a club-shaped manner, are met with (pi. XV, f. 8, 9). 



The scopules are numerous, arranged vertically to the surface and variable 

 in shape. They have 4-6 branches which lie between the proximal, radial rays 

 of the dermal hexactines and nearly reach the surface. The shaft is generally 

 simple, straight, 400-500 h- long and gradually attenuated towards the pointed end- 

 It is always rough terminally, but for the remainder of its length either rough 

 or smooth. The number, shape and direction of the dermal branches are sub- 

 ject to considerable variation. Most frequently four stout diverging dermal 

 branches are observed, which arise from a comparatively short thickening at the 

 distal end of the shaft. The basal part of each branch is thin, about 10 p- long, 

 and extends at first upwards in a pretty straight line, it is then bent outward 

 more or less sharply. The free distal part, lying beyond the bend, is about three 

 times as iong as the basal part and, below, of about the same thickness as the 

 latter. Towards the end it is thickened in a club-shaped manner and it termin- 

 ates with a convex, cupola-like transverse disc, bearing a verticil of marginal 

 teeth. These vary in length, are pointed and directed outwards and backwards 

 (pi. XV, f.2). The branches themselves are either quite smooth or covered with 

 small and slender, oblique spines, directed backwards. Of the other kinds of 

 scopules the one most different from this kind is pretty rare. This scopule also 

 has four branches, but differs from the one described above by the following 

 peculiarities. The distal thickening of the shaft is stout and caliculate and the 

 branch-rays arise from its margin and extend upwards towards the surface, 

 nearly parallel to each other. They are nearly cyhndrical, slightly thickened in a 

 knot-shaped manner at the distal end and uniformly and closely covered in their 

 entire length with very slender spines, directed obliquely backwards. The term- 

 inal thickening is covered with similar, but shghtly stouter spines. Besides 

 these rare scopules with nearly parallel cylindrical dermal branches, other, similar 

 ones, in which the dermal branches diverge more strongly or are more or less 

 abruptly bent outward below the middle, occur a httle more frequently. One 

 of the former is represented in fig. 10, one of the latter in fig. 11 on plate XV. 

 12 



