AND ITS KELATIONS TO KECEtfT COMATUL^!. 215 



ceous Comatulce, the basals are the embryonic basals which have 

 undergone no farther modification than those of many Pentacrinus 

 species. Their relative size is reduced, as they do not quite 

 separate the radials from the top stem -joint, even when they 

 appear externally, which is not always the case, both individuals 

 and species varying greatly in this respect . 



2. In all the recent Comatulce (possibly also in the Tertiary 

 and in some Cretaceous species) the embryonic basals undergo an 

 extensive modification resulting in the formation of a rosette. In 

 many cases basal rays extend outwards from this and may appear 

 externally ; but they are only analogous and not in any way 

 homologous to the true basals of the older Comatulce. , 



3. Most Pentacrini have a more or less complete circlet of 

 basals separating the top stem-joint, either partially or wholly, 

 from the radial pentagon. But in some few fossil forms there 

 are no external basals, as may be also the case in PJncrinus. 

 There is thus a parallel variation to that occurring in Comatula, 

 but with a different range, for we know of no Comatula (recent or 

 fossil) in which the basal circlet is complete, and of no recent 

 Pentacrinus in which no basals appear externally. 



4. The variations in the development of the basals are useless 

 as generic distinctions. P. Fisheri, P. briareus, and P. Sigma- 

 ringensis among the fossil forms, with the recent P. asteria and P. 

 Wyville-Thomsoni, are all equally good species of Pentacrinus. In 

 the same way Ant. costata with small basals, Ant. scrobiculata with 

 large oues, and Comatulina or Decameros with none visible ex- 

 ternally are just as good species of Antedon as Ant. rosacea, which 

 has only a rosette, and Ant. macro enema, which has basal rays as 

 well. 



Schliiter, therefore, was perfectly justified in uniting Solano- 

 crinus with Antedon. He does the same with Comaster, though 

 from Goldfuss's description of this type it appears to me to differ 

 so much from all other Comatulce that I prefer, for the present, 

 at any rate, to regard it as generically distinct from the other 



5*. 



In conclusion, I desire to record my obligations to Prof. 

 Hughes, and to Dr. H. "Woodward, F.E.S., and Mr. E. Etheridge, 

 jun., for the readiness with which they have permitted me to 

 examine specimens in the Woodwardian and British Museums 



* See Journ. Linn. Soc. Zool. vol. xiii. pp. 454-456. 



