RCHINOIDEA. I. 8l 



2. The tube feet on the actinal side in a single, almost regular 

 series; the test very soft 3. 



The tube feet on the actinal side in three more or 

 less separated series 5. 



3. Ophicephalous pedicellariae are found Tromikosoma Koehlcri Mrtsn. 



Only tridentate and triphyllotis pedicellariae 4. 



4. The tridentate pedicellarise simply leaf-shaped Echinosoma uranus (Wyv. Thomson). 



The tridentate pedicellariae with much involuted blade, 

 the point widened in a spoon-like manner with straight, 

 finely serrate edge Hygrosoma Petersii (A. Agass.). 



5. The three series of tube feet rather close together; the 

 ambulacral areas of the common structure; the tridentate 

 pedicellariae not simply leaf-shaped. The hoof small 6. 



The three series of tube feet widely separated; the 

 ambulacral areas on the actinal side formed by 8 series of 

 plates. Tridentate pedicellariae simply leaf-shaped, the 

 largest ones with a rich, thorny net of meshes filling the 

 blade. The hoof large : Sperosoma Grimaldii Koehler. 



6. The large tridentate pedicellarise with much involuted 

 edge; the widened part of the point finely, but irregularly 

 serrate in the edge; the smaller tridentate pedicellarise of 



a similar structure Calveria hystrix Wyv. Thomson. 



The large tridentate pedicellariae with much involuted 

 edge ; the widened part of the point is deeply and coarsely 

 indented in the edge. Tetradactylous pedicellariae may be 

 found 7. 



7. The smaller pedicellariae with the widened part of the 



point coarsely sinuate in the edge Araosoma fencstratum Wyv. Thomson. 



The smaller pedicellariae with the widened part of the 

 point of the blade straight and finely serrate in the edge. 

 Moreover a very large form is found with coarsely in- 

 dented edge Arczosoma Belli Mrtsn. 



Fam. Temnopleuridae. 



Hypsiechinus n. g. 



The test generally without distinct grooves or furrows; no distinct slits in the edge of the 

 mouth. The buccal membrane covered with large plates; all the buccal tube feet are generally well 

 developed in the adult individuals. None of the ocular plates reaches quite to the periproct, which is 



The Ingolf-Expedition. IV. I. jj 



