EXPLANATION OF THE PLATES. 133 



Fio-. 4. Same as Fig. 2, seen from tlie abactinal side, to show the network of the abactinal surface and 



the projecting knobs forming the support of the clusters of spines of that surface. 

 Fif. 5. Lonwitudinal section through the median line, seen in profile. 



All figures natural size. 



The coloring of tliis species is of all shades, between a brilliant red and a light orange or a dark violet. 



PLATE XIII. 



Pycnopodia helianthoides. 



Fig. 1. Portion of disk, seen from .ibactinal side, -with papillte fully expanded (from life). 



Fig. 2. Same as Fig. 1, seen from the actinal side. 



Fig. 3. Actinal view of central part of the disk, showing the connection of the arms around the central 



opening. 

 Fig. 4. Limestone network of part of the abactinal membrane, with the pillar separating adjoining arms 



seen from the interior. 

 Fig. 5. Profile view of the extremity of one arm. 

 Fig. 6. Interior view of the arm ; the abactinal membrane is removed, showing the mode of connection of 



adjoining arms at actinostome, ambulacral vesicles all removed. 

 Fig. 7. Same as Fig. 6 ; seen from below, the soft parts all being removed. 

 Fig. 8. Profile view of Fig. 6. 

 Fig. 9. Section across Fig. 6. 



Fig. 10, 10". Profile views of two of the large spines of the abactinal surface. 

 Fig. 10', 10'". The same spines, 10, 10", seen from above. 



Figs. 1-5 are natural size ; all others slightly enlarged. 



The color of tlie abactinal surface varies greatly in this species, from a brilliant carmine to yellow, violet, or bright 

 vermilion, with the intermediate shades of orange. 



PLATE XIV. 



LiNCKIA GUILDINGII. 



Fig. I. Seen from above. 



Fig. 1'. Enlarged tip of one of the arms. 



Fig. 2. Fig. 1, seen from the actinal side. 



Fig. 2'. Magnified portion of arm of Fig. 2. 



Fig. 3. Preparation of actinal side, showing the limestone plates after the granulation is removed. 



Fig. 3'. Magnified -view of opening of actinostome of Fig. 2. 



Fig. 4. Preparation of abactinal surface, showing the limestone plates of that surface. 



Fig. 4'. Enlarged view of madreporic body. 



Fig. 5. Interior view of abactinal surface of one of the arms, showing the small openings left between the 



nearly united plates. 

 Fig. 6. Section across one of the arms, to show the depth of the ambulacral furrow, with its single line of 



ambulacral pores. 



Linckia is generally of an ashy-violet color, with darker spots scattered over the abactinal surface of the arms. 



ASTERINA FOLIUM LiUk. 



Fig. 7. Actinal view prepared to show the plates of that surface. 



Fig. 7'. Enlarged view of plates, forming edge of actinal opening, in Fig. 7. 



Fig. 8. Somewhat enlarged view, natural attitude, with suckers expanded. 



Fig. 8'. Enlarged view of arm, showing ocular tentacle, at ba=e of pointed terminal ambulacral tube. 



Fig. 9. Water-tubes of abactinal surface somewhat enlarged. 



Figs. 1-7, natural size ; others somewhat enlarged. 



The abactinal surface of Asterina is of a pea-green color. The actinal surface is more yellowish. Specimens frequently 

 occur of a yellow color on both sides. 



