146 
R. Rathbun — List of the Brazilian Echinoclerms. 
very much broader than the above, but not much longer, clavate in 
general form, with compressed tips, not arranged regularly in longi- 
tudinal rows, but in short, slightly oblique series of two, seldom 
three, spines. Between the ventral and adambulacral rows of spines 
the intervening space is very narrow, but the ventral and lateral rows 
are widely separated. The lateral and dorsal spines are all of sub- 
equal size, very small and short, about one-half as long as the adam- 
bulacral or even shorter, cylindrical, or slightly tapering, and with 
truncate, rounded ends. First above the ventrals comes a single 
row of these spines, rather widely separated, and arranged one to a 
plate, seldom two, with sometimes a short lower row, of six or seven 
smaller spines, near the middle of the arm. Above the first lateral 
rows of each side, we can distinguish in all five longitudinal series of 
spines, including the median dorsal one. In these series the spines 
are not generally regularly placed, but we can make out a certain 
arrangement among them. The first series consists usually of two 
rows of alternating spines, distinct nearly or quite to the tip of arm. 
The second series, toward the disk, is made up of successive, irregu- 
lar or slightly curved, transverse rows of four or five spines, with an 
intervening spine to connect the several rows ; farther out the series 
becomes reduced to a single, irregular, longitudinal row of spines. 
The median dorsal series is formed of similar transverse rows of about 
five spines each, arranged irregularly in the shape of a very broad V, 
with the angle turned toward the disk; toward the tip there are only 
two or three spines to a group. Near the disk there are many addi- 
tional spines scattered over the arms, more or less obscuring the 
above arrangement. The spines of the disk are similar in character 
to those of the rays, and of the same size or slightly smaller ; they are 
closely arranged but without order. 
The major pedicellariae are very large and numerous, being scat- 
tered over the entire surface of the rays and disk. Where perfectly 
preserved, they are elongate triangular in outline, with strongly 
curved base, and are about two-thirds as broad as long ; they often 
appear ovate in outline. They vary in size, many being only one- 
half or two-thirds as long as others. The larger ones equal or 
slightly exceed the lateral and dorsal spines in length, and are very 
much broader. Everywhere above the first lateral rows of spines, 
they are about uniformly distributed, ranging most commonly along 
the edges of the plates. Between the ventral and lateral rows of 
spines, they are much more numerous, being especially abundant 
just above the bases of the ventral spines. They also occur, but more 
