446 CAEPENTEE AND VON GEAFF OX METACBINUS AND MYZOSTOMA. 



DESCRIPTION OF THE PLATES. 



Plate L. 



Metacrinus rotundus, sp. n. 

 Fig. 1. The bead and upper part of the stem. Natural size. 



Fig. 2. The disk, from above. x 3. 



Plate LI. 



Me/acri/nix superbus, sp. n. 

 Fig. 1. The head and upper part of the stem. Natural size. 

 Fig. 2. Portion of an arm, rather below its middle, from the right side. x 2. 

 Fig. 3. Terminal portion of an arm undergoing regeneration, showing the growing points of its two 



divisions, x 2. 

 Fig. 4. Terminal portion of a full-grown arm, with imperfectly developed pinnules. x 2. 

 Fig. 5. The ambulacra! groove, with its branches on to the pinnules, viewed from above. x 5. 



Plate LI I. 



Figs. 1-7. Metacrinus rotundus, sp. n. 

 Figs. 1-4. Stem-joints, x 0. Fig. 1. Ordinary internodal joint. Fig. 2. Nodal joint ; lower or syzygial 



face. Fig. 3. Nodal joint ; upper face. Fig. 4. Supranodal joint ; lower face. 

 Fig. 5. Fragment of stem, showing the cirrus-sockets on the nodal joiut. x 2. 

 Figs. 6 & 7. Side views of pinnule-ambulacra. x 25. 



Figs. 8-12. Metacrinus superbus, sp. n. 

 Fig. 8. Nodal stem-joint ; upper face. x 4. 

 Fig. 9. Ordinary internodal joiut. x 4. 

 Figs. 10 & 11. Side views of piunule-ambulacra. x 25. 

 Fig. 12. Fragment of stem, showing the cirrus-sockets on the nodal joint, x 2. 



Figs. 13-18. Metacrinus Stewarti, sp. u. 

 Fig. 13. The stem-fragmeut. Natural size. 

 Figs. 14-17. Stem-joints. x 6. F'ig. 14. Nodal joint; upper face. Fig. 15. Nodal joint; lower or 



syzygial face. Fig. 16. Intranodal joint ; upper or syzygial face. Fig. 17. Ordinary internodal 



joint. 

 Fig. 18. Fragment of stem, showing the cirrus-sockets on the nodal joint. 



Fig. 19. Myzostoma cirripedium, sp. n., seen from the ventral side, x 28. t. Marginal cirri ; cl. Cloacal 

 opening ; *. Intestinal ramifications (indicated only on the left side of the figure) ; m. Mouth ; 

 od. Oviduct; p. Parapodia; pc. Parapodial cirri; ph. Bulbus musculosus of the Pharynx; s. 

 Suckers; st. Stomach ; $ . Male genital openings. 



