ECHINOIDEA. I. 8l 



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

 series; the test vexy soft 3. 



The tube feet on the actinal side in three more or 

 less separated series 5. 



3. Ophicephalous pedicellariæ are found Tromikosoma Koclilcri Mrtsn. 



Only tridentate and triphyllous jpedicellariæ 4. 



4. The tridentate pedicellariæ simply leaf-shaped Echiuosoma uramis (Wyv. Thomson). 



The tridentate pedicellariæ with much involuted blade, 

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

 finel}- serrate edge Hygrosoma Peter sii (A. Agass.). 



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

 ambulacral areas of the common structure; the tridentate 

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



The three series of tube feet wideh- separated; the 

 ambulacral areas on the actinal side formed by 8 series of 

 piates. Tridentate pedicellariæ simply leaf-shaped, the 

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

 blade. The hoof large Spcrosoma Grimaldii Koehler. 



6. The large tridentate pedicellariæ with much involuted 

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

 serrate in the edge; the smaller tridentate pedicellariæ of 



a similar structure Calveria Jiystrix Wyv. Thomson. 



The large tridentate pedicellariæ with much involuted 

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

 indented in the edge. Tetradactylous pedicellariæ ma}- be 

 found 7. 



7. The smaller pedicellariæ with the widened part of the 



point coarsely sinuate in the edge Ar æosoma f enestratum Wyv. Thomson. 



The smaller pedicellariæ 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 Ar æosoma Belli Mrtsn. 



Fam. Temnopleuridæ. 



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 piates; all the buccal tube feet are generally well 

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



The Iiigolf-Expedition. IV. i. H 



