82 The Ottawa Naturalist. [Oct. 



finds, however, that "they are not far from their original position" 

 (p. 107, lines 18-19). That they were thrust to their present 

 position after the burial of the specimen is made manifest, not 

 only by the plates in the immediate vicinity, but plates now 

 lost must have communicated this thrust to interradius 1, and 

 there not only turned the secondary jaws, but displaced one of 

 the mouth plates and the oral. Dr. Raymond's assertion that 

 "if these were plates foreign to this specimen, they would not 

 maintain their natural position in relation to each other, but 

 would be separated," is evidently meant to indicate that the 

 overriding movement was not of great magnitude. He must 

 have frequently found forms buried seriallv over each other, 

 without necessarily finding all the plates of the upper specimens 

 "separated." An examination of our plate VIII, fig. 1, with a 

 stereoscope leads me to doubt if (y) belongs to (x) anv more 

 than (z) does. I find plate (y) depressed; the meeting faces 

 neither parallel nor of the same form; and if the plate really 

 belonged to (x) shifted a little toward radius I, though I should 

 have expected the thrust to have made it slip in an opposite 

 direction. The movement instead of separating these plates has 

 thrust them together. Dr. Raymond asserts that (y) cannot be 

 an adambulacral of another specimen (p. 107, lines 12-14) 

 because it "is larger and of different shape." It has two dia- 

 meters perpendicular to its sides of about 0.8 mm each, which 

 is a little less than the transverse diameter of the adambulacral 

 just back of the undisturbed mouth plate in radius II. Turn 

 this adambulacral on its side and you will have a plate displavin- 

 an area greater than that now shown by (v). Plate (x) "is 

 pointed at the wider end " (p. 107, line 6), but I cannot be positive 

 that the faces on each side of the angle are either true sutural 

 faces or that this is the original orad end of the plate. The 

 smaller face seems to possess the granular ornamentation of the 

 aborad end of a marginal and the lines of blackened organic- 

 fragments buried in the plate run parallel to the long face while 

 in the stereograms .(photographs) these lines are distinctlv sub- 

 parallel with the sides next the first arm marginals. If plate (v) 

 belonged to the aboral skeleton it is sheltered enough to have 

 retained some ornamentation, but it is as smooth as a sutural 

 face of an adambulacral. As all other plates have been com- 

 pletely weathered away we must credit the remaining big plate 

 with a serious loss of its original surface. I would not like to 

 assert of this plate, which shows rotation on both its long and 

 short axes in addition to great loss of surface, that it has the 

 "same form" (p. 107, line 19-21) as an interradial supero- 

 marginal of Palaeaster matutina, Hall. 



