55 



Family RHODOCRINID^. 



goniastehoidocrinus lyonanus, d. sp. 

 Plate IV. Fiii\ 4, view of the vault and lateral prolongations. 



This species is founded upon the vault and lateral prolonga- 

 tions of the specimen illustrated. It is quite different from any- 

 thing heretofore described or illustrated, and, therefore, deserves 

 illustration and definition. Whether or not one is justified in 

 giving a specific name to such a fragment is a question not so 

 readily answered. A specific name should not be an obstacle in 

 the way of progress, in pala>ontological learning. It requires 

 neither information nor study to propose specific names, and 

 when impi'ovidently or unjustifiably proposed, they should not 

 be recognized. We think, as a general rule, a specific name 

 should never be given to a specimen, when, from its definition, 

 another who may happen to find a better specimen, in rocks of 

 the same age, cannot determine whether or not it belongs to 

 the same species. We have here, however, a very complete part 

 of the body of a peculiar crinoid, about the generic relations of 

 which there is no doubt, and, we suppose, whenever the calyx 

 is found, after our definition of this part, that one may readily 

 determine that it belongs to this species, and it is for that rea- 

 son we have felt warranted in giving to it a specific name. 



Species rather small. Vault composed of small polygonal 

 plates. Central part of the vault only slightly raised above the 

 lateral margin and composed of the larger plates. Instead of 

 a single proboscis arising from the center of the vault, as in 

 many palteozoic genera, there ai-e six lateral prolongations, five 

 of which bifurcate, and one tapers to a point without a bifur- 

 cation. There is a shallow, subovate depression, within the 

 margin, opposite each one of the five bifurcating lateral pro- 

 longations, but none opposite the .single prolongation. Within 

 one of these depressions, near the center of the vault, there is 



