232 ART. 2. — H. MATSUMOÏO : 



very light pink. The verrilli-type is closely similar to the isidicola- 

 type, so that the two are practically one. I imagine that on an 

 average, the isidicola-type (including the verrilli-type) has greater 

 bathymetrical range than the dance-type. 



In some specimens, there are as many as seven arms. Again, 

 a few of the disk grannies may be conical and pointed. In some 

 of the dance-type, the dorsal surface of the disk is entirely free of 

 erranules or tubercles. 



Order iv. chilophiurida Matsumoto. 



Disk covered with scales or plates, often with superficial 

 granulations. The radial shield and genital plate on the same side 

 of a radius articulate with each other by means of two articular 

 condyles and one pit on both the plates. Peristomial plates double 

 or triple, not very large. Oral frames witli or without well 

 developed lateral wings. Oral papillae well developed, close-set, 

 very often entirely closing the oral slits ; the outermost one being 

 pointed inwards above the next papilla which is the largest, but 

 sometimes modified in certain ways by the displacement of the 

 second oral tentacle pores outside the oral slits. Arms only 

 horizontally flexible, the vertebral articulation being zygospondyline. 

 Arm plates usually all well developed. Arjii spines very short or 

 long, lying flat on the arm or erect. 



Key to families of CMlophhtrida, 



A — Arm spiues short, lying flat on the arm. 



« — Disk usually free of granules; second oral tentacle pores opening 



