4 PORIKERA. II. 



o-057 mm , the greatest breadth is 0-020 — 0-022™'", and the thickness of the shaft is o-oo2 mm . These chela- 

 are frequently found in rosettes. Quite single chelae of smaller size are found, down to 0'03 mm . 2. The 

 other silicious body found in the sponge is of a peculiar shape, and on account of its smallness 

 and intricate structure it is difficult to get a clear view of it. Its form may be reduced to the aniso- 

 chelate type. Below it consists apparently of a jar- or slipper-like part and above of four alse issuing 

 from the upper end, which alse on four sides extend down over the slipper-like part. The lower part 

 looks somewhat differently, according as the bod)- is seen from one or the other side, and by a preli- 

 minary examination only two of the four alse are seen, one on either side. By a more thorough 

 examination under sufficiently high magnifying powers it is seen that, when the chela is in a certain 

 position, an axis runs along one side, below turning upward to about the middle of the chela; when 

 the chela is placed in such a way as to turn the axis behind, i. e. away from the beholder, the form of 

 the lower part is all but slipper-like; the exact form of this part is only to be seen with difficulty, but 

 it appears to consist, as usual, of lateral alse issuing from the axis, and of a broad tooth before. Both 

 the alse and the tooth are on the sides folded towards each other, the interstice between them I have 

 not been able to see with certainty, but it is about as shown on PI. X, fig. 2 c. On either side the axis 

 of the chela is in its upper part provided with rather narrow alse separating from the axis about in 

 the middle, and continuing downwards as a single pointed elliptical tooth. Further a free, pointed 

 elliptical ala is found on either side with the flat sides turned laterally, and in the front is found a tooth 

 of the same form. These structures are placed at equal distances from each other, and form the four 

 apparently uniform ake, which pass from above downwards to about three fourths of the length of the 

 chela. The two lateral alse together with the alse of the dorsal side may be regarded as corresponding 

 to the alse of the axis of a common chela. That the lateral alee are not teeth may be seen from the 

 fact that above they are provided with an unsymmetrical, translucent part, while in the tooth there is 

 a symmetrical tuberculum; they are likewise above and behind connected with the ala of the dorsal 

 side. The alse as well as the tooth are best seen when turned to the side so as to be seen from the 

 edge, whereas, when turned towards the beholder, they are only to be seen with much difficult} - , on 

 account of their fineness and transparency. A good view of the mutual position of the parts ma}- be 

 got, when the chela is seen from the end in such a way, that the lower end is turned directly towards 

 the beholder, who will then see an optical transverse section as fig. 2 f, PI. X, where the tooth, the two 

 lateral ake, and the axis are seen at right angles to each other, and in the middle the lower part in 

 connection with the axis and its alse. These chelse are very small, their length varying from 0-012— 

 o-oiy"" 11 , and the breadth being 0-007 — ooo8 mi ". Both the large palmate chelse and the small peculiar 

 ones occur abundantly. 



This species so peculiar and characteristic by its spiculation has by Vanhoffen 1. c. been 

 determined as E. intermedia O. S. As I have had preparations of the specimens of Vanhoffen, I have 

 been able to decide with certainty thas it is the present species he speaks of. Vanhoffen has, strange 

 to tell, made a mistake with regard to the megascleres, and calls them beiderseits zugespitzte », whereas 

 the are distinct styli. Schmidt says of his Esperia intermedia that it has < unspitzige Nadeln , 

 which I take to be a misprint for <umspitzige>, and further his species is provided with two different 



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