SHALLOW- WATER STARFISHES 313 



region of the rays and over the disk they are spino-parapaxillae, each 

 bearing a long, tapering, acute central spine, surrounded at base 

 by a circle of small spinules. Between the plates there are, over 

 nearly the whole surface, numerous papular pores. Along each ray, 

 toward the marginal plates, there are, at irregular intervals, singu- 

 lar pectinate pedicellariae, consisting of groups of small incurved 

 spinules. Usually there are two, three, or four clusters. Each 

 cluster, consisting of a row of three or four to six curved spinules, 

 form one group ; and the ends of all the spinules converge to a pore 

 in the center of the group. A much larger elliptical one, composed of 

 ten to twelve spinules on each side, occupies each actinal interradial 

 area. 



The upper marginal plates are small, but prominent, and each 

 bears a long, rather stout, acute, erect spine, surrounded at base by 

 a group of slender, unequal spinules. The lower marginal plates 

 mostly bear three long and large divergent spines, the upper one 

 largest, and rather longer than those of the upper plates; between 

 and around their bases there are slender spinules. The adambulacral 

 plates bear upon the inner edge a rounded group of about six very 

 slender, blunt spines ; the two lateral ones are very short ; the middle 

 ones, long; outside of these there is a transverse row, usually of 

 three much longer and larger blunt spines. 



Dixon Entrance, British Columbia, n fathoms (type, collected 

 by Dr. G. M. Dawson, 1885). 



Dr. Fisher records it from eleven stations, in 56 to 159 fathoms, 

 from Bering Sea to Kadiak, Alaska. 



Suborder PAXILLOSA (Perrier), emended. 



Paxillosa PERKIER (as an order), Exped. Trav. et Talism., pp. 28, 29. 

 Paxillosa VERRILL, Trans. Conn. Acad., x, pp. 199, 200, 201, 1899. 



These are Phanerozona in which the two rows of marginal plates 

 are usually well developed and often spinose, and usually have well 

 developed fasciolate grooves between them. The dorsal or abactinal 

 plates are usually developed in the form of true columnar paxillae 

 or spinopaxillae, sometimes as pseudopaxillae. Pedicellariae are often 

 present, usually consisting of several connivent papillae, or spinule- 

 like structures, surrounding a pore. Sometimes forceps-like forms 

 occur. 



Bivalve valvular pedicellariae are lacking. Ambulacral feet are 

 generally pointed; sometimes flattened and natatory; rarely with a 

 small terminal knob, but without a sucker. 



