SHALLOW-WATER STARFISHES 297 



width of the proximal half of the rays, as well as most of the central 

 disk. In these areas the plates are rounded or elliptical, convex, 

 somewhat elevated, and separated by intervening spaces, in which 

 there are usually five or six groups of papular pores, the individual 

 pores being small and unequal, two or three or more forming each 

 group. 



Each of the larger abactinal radial plates is covered with a rosette 

 consisting of about five to seven central and twelve to fourteen mar- 

 ginal, short, blunt, or clavate, granule-like spinules, rather longer 

 than broad. Some of the disk-plates are larger, with more spinules. 

 A large valvular pedicellaria often replaces the central group of 

 spinules on some of the plates. These occupy nearly the whole 

 breadth of the central area of the plate, and are narrowly oblong, 

 not much elevated, with a nearly even and straight margin. Similar 

 pedicellariae, as well as some narrower ones, occupy the central area 

 of some of the interactinal disk-plates. 



The madreporic plate is small, sunken, with narrow, acute gyri. 

 The central nephridial pore is small but distinct. 



The actinal disk-plates are crowded and closely united ; those next 

 the adambulacral plates are squarish or rhombic and form regular 

 rows, but those in the angles are smaller, irregular, and more 

 rounded. All are covered with rosettes of granules, or short, obtuse, 

 often prismatic spinules, rather larger and less regular than those of 

 the upper side. A central valvular pedicellaria occurs on some of 

 the plates, as stated above. 



The adambulacral plates are squarish, not very large. Each bears 

 a marginal row of three or four small, oblong, more or less prismatic 

 or compressed, blunt spinules, the middle one usually a little larger 

 than the others. External to these are two sets of shorter spinules, 

 about three in each series ; these sometimes form two rows, but in 

 other cases are in a rosette-like group. Those next the inner or 

 groove-series are longer than the others. One or more of these, 

 especially distally, may be replaced by a spinuliform pedicellaria 

 with two or three blades. On the distal part of the ray one or two 

 of the spinules on the central part of these plates becomes consid- 

 erably longer and larger than the rest. The oral spinules are similar 

 to the adambulacral, but those at the tip of the oral plates are rather 

 larger and more angular. The apical plates are rather small, promi- 

 nent, somewhat obovate. 



The preceding description is from a Californian specimen. 

 I have examined a natural-size photograph of the type of this 

 species, furnished by Dr. R. Rathbun. It differs from the specimen 



