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ECHINOIDEA. I. 



33 



cellariae, and therefore I only mention the featnres being of systematic importance; for the rest the 

 reader is referred to the figures (PI. VIII. Fig. 27. PI. IX. Figs. 3, 5, 7, 13-15, 20, 25, 27). 



At the point of the large globiferoiis pedicellarite (PI. IX, Fig. 3, 5) is found a distinct tooth sepa- 

 rated from the opening on the inside of the blade by a distinct curve; seen from the inside it appears 

 as a long narrow point before the upper edge of the opening. A canal is seen to run through this 

 point, and open on the upper side of the tooth — this canal is the efferent duct from the poison- 

 or mucous gland enclosed by the blade. The inner opening is large, lengthened, most frequently run- 

 ning into a narrow point below. The edge round the opening is more or less thickened, with 

 numerous small teeth and a few large ones placed irregularly. The outside of the blade is highly and 

 irregularly perforated almost to the very point. The stalk of these and of the other pedicellarise con- 

 sists of a highly irregular, complicated calcareous network, with no conspicuous free points (limb) at 

 the transition between the thick and the thin part. The length of the head is about i"""; the length 

 of the stalk is somewhat different, but generally it is very short, even shorter than the head. They 

 are found especiallv on the apical area, but also in the interambulacral areas, mostly on the 

 naked spaces. 



The small globiferous pedicellaria; (PI. IX. Figs. 13—15, 20) are upon the whole constructed as 

 the large ones; the tooth at the point is considerably smaller, may be very slightly developed. The 

 inner opening is comparatively larger than in the large globiferous pedicellarise; the lower edge ma\- 

 also here be irregular. They are more long-stalked and upon the whole much more .slender than the 

 large ones. They are especially found among the small spines round the radioles and on the peri- 

 stome, but may otherwise be scattered over the whole test. 



The tridentate pedicellariae (PI. IX. Figs. 7, 25, 27) are large and .slender: the head is 1—2'"'" 

 long, the length of the stalk is very differing, but commonh- it is considerably longer than the stalk 

 of the large globiferous pedicellarise. The blades are narrow, straight, and join close together in their 

 whole length, when shut, or are at all events only apart for a very little space below. The edge is 

 somewhat thickened and highly dentate; at the transition between the base and the blade the edge 

 is often very irregularly serrate. The blade is narrow and deep, filled by an irregular network, which 

 is often, in the lower part of the blade, provided with fine teeth; in the outer part of the blade most 

 frequently only cross-beams are found connecting the edges with each other. These pedicellarise are 

 especially found in the middle of the ambnlacral areas towards the mouth. In some individuals they 

 seem to be quite wanting. 



The spicules of the tube feet (PI. XL Fig. 26), as is known from Perrier and Wy v. Thomson, 

 are bow-shaped and rather highly thorny. They are situated in two series in the .skin of the tube foot, 

 so as to join each other along one side of the foot — not, however, in a definite line, the ends 

 catching irregularly in between each other. On the other side they are widely scattered; thus the tube- 

 foot is closely mailed for ^/^ or 2/3 of its circumference, the other part is naked (PI. VIII. Fig. i). The 

 naked side seems always to be the oral one; in this side the tentacle-nerve is lying, as shown by 

 Prouho (op. cit). Otherwise he also gives a quite correct description of the way in which the spi- 

 cules are arranged in the tube-feet. — Down towards the base of the tube-foot the spicules become 

 shorter and less thorny, and here they do not join on either side, and are thus arranged in two com- 



The Ingolf-Expedition. IV. I. 5 



