24 The Ottawa Naturalist. [May 



arm. Before figure 1 of this plate had been made much of this 

 blackened bed had been removed from the interradii 1 and 2 

 in order to photograph the arms from the side. 



The specimen is so perfectly preserved and so free from 

 distortion that we are not warranted in supposing that any 

 large portion of the oral surface could be lost. The thick 

 blackened layer is so loosely constructed and filled with minute 

 flakes or grains of calcite (although these or many of them may 

 be due to subsequent infiltration and crystallization) that we 

 are obliged to interpret it as the remains of a thick leathery 

 integument reminding us of the muscular integument of the 

 Holthuroidea or more properly of the aboral integument of 

 most of the Streptophiurae and of the Cladophiurae. 



Further development may yet reveal traces of the radials 

 and perhaps genitals but this should be undertaken only by 

 some person whose knowledge of both the Asteroidea and Ophiu- 

 roidea is extensive, whose authority would be unqestioned and 

 whose skill would be adequate for the task. Very valuable 

 evidence might easily be destroyed and lost forever. It is 

 possible that the plate here called "torus," belongs to an aboral 

 circlet. Interradius 1 with its pieces composing the secondary 

 jaw displaced and showing that the}- were not fixed to either 

 the "torus?" or the fir.-, pair of adambulacrals but were bound 

 to each other, should be left as it is. Interradius 2. with the 

 secondary jaw in normal position, and interradius 3. with its 

 first epineurals but slightly displaced, should also be left as thev 

 are. Interradius 5 should have the secondary jaw carefullv 

 removed to see if the "torus?" really rested against the orad 

 ends of the adambulacrals and [o fully reveal the oral aspect of 

 the latter. Search should also be made for the madreporite of 

 this species. 



Taxonomy. 



There is enough now clearly shown by this specimen to 

 make it very manifest that we are dealing with an unrecognized 

 and very archaic morphological type which links the Edrioaster- 

 oidea with the Stelleroidea. Were it not for evidence I have yet 

 to present as to habit, I should unquestidningly place this 

 specimen with the Edrioasteroidea for it is almost as simple in 

 its elements as Cystaster, Hall. On account of its stelleroid 

 habit and the fact that we 'have described Stelleroidea which 

 are closely related to it I feel that it should be retained in the 

 latter class. In either case the type should be recognized. 



EOSTELLEROIDAE, ORD NOV. 



This order is proposed for those Stelleroidea in which true 

 ambulacrals (in the sense in which the term is used in this class) 



