Anatomy of the Temnopleuridifi. 129 



curled around neighbouring structures after death ; thej are 

 continuous with the outer tissue of the stalk, and are exces- 

 sively fragile. 



2. Common tridactjle pedicellarige with smaller valves 

 than the above, the base wide and suddenly diminishing, the 

 prongs narrow, slender, very wide apart, long, and ended by 

 a sharp curved point, below which are two others, one on 

 each side (fig. 23). The whole is fenestrated. The largest 

 of these forms are seen actinally, as well as close to the apical 

 system, and around the bases of the large spines. The 

 ambulacro-interradial sutural region is a common spot. 



Smaller tridactyles with slightly stouter prongs are very 

 common, and are found very generally distributed. 



Both of these forms of tridactyles often have long, soft 

 necks and are placed upon long or short spinules ; some are 

 without necks, and are either sessile or with stalks. 



3. The globifera (fig. 24)* are very common, and there 

 are a few very large ones near the apical system and a host 

 of smaller forms very generally placed, and notably along 

 the ambulacra and the median area of the interradia. Tlie 

 large and small have the same structure. The base is broad 

 and tumid, gracefully merging into the broad, moderately 

 long, broad, boldly curved, slightly angularly-ending prongs. 

 The sides of the valves are distantly serrate, and a stout cal- 

 careous ridge runs along the median line, and has lateral off- 

 shoots, and in the hollows between are minute openings. 

 This is a very marked character. These pedicellariaa are, as 

 the others, either placed upon soft necks or upon stalks of 

 varying length, some 1 millim. 



4. The triphyltaor ophiocephalous pedicellari^ (fig. 25) are 

 in vast numbers, and are at once recognized by their very small 

 size, their blunt free ends, tumid subcylindrical shape slightly 

 longer than broad, and their very minute perforations. They 

 have very blunt terminations to their valves, no teeth, and 

 when looked at from above a trefoil appearance is seen. Thev 

 occur in vast numbers in the actinal region of the ambulacra 

 and around all primary and secondary spines, around many 

 tentacles, and upon the radial plates. There are none upon 

 the peristomial membrane or upon buccal plates. Most are 



• The globifera of authors, not especially of Otto Hamann, who would 

 term them gemmiformes. The globifera of that excellent microscopist 

 are large tumid tripartite glohose-looking pedicellariae without calcareous 

 heads, and with a very strong muscular layer. They secrete, and are 

 according to Hamann, very generally found on certain species of Echi- 

 noidea. I have evidence of their occurrence in TemnopleurtiSy near the 

 apical disk, although I was not fortunate enough to discover them ia 

 Sph(sr echinus. 



