88 On the Generic Position of Solanocrinus. 



shows that it must have taken place at a syzjgy ; while the 

 unusual shortness of the preceding joint points to the same 

 conclusion. 



I have gone into this question more fully than would have 

 been desirable in the Report on the ' Challenger ' Comatula?, 

 because I wished to explain in detail my reasons for still re- 

 garding Solanocrinus as a synonym of Antedon, and not as 

 an independent genus. There are many recent Comatulge in 

 which syzygies are comparatively rare upon the arms, only 

 occurring at intervals of twenty joints or so ; and I cannot 

 but think that Walther has been a little premature in attempt- 

 ing to revive Goldfuss's genus. The progress of research 

 may ultimately reveal other characters which will give Solano- 

 crinus a definite generic position, but at present I cannot 

 admit that it has any claim to be separated from Antedon. 



There is much more in Walther's memoir which I should 

 like to discuss at length. He calls the primary tentacles 

 which are extended from the water-vascular ring of the Penta- 

 crinoid larva " Embryonal- Pinnulse ;" and he further says 

 that they have no great resemblance to the tentacles which 

 ultimately appear in connexion with the radial water-vessels 

 along the sides of the brachial ambulacra. This is a suffici- 

 ently remarkable statement, but it is altogether eclipsed by 

 his assumption " dass die Embryonal-Pinnulse den definitiven 

 Pinnulis homolog sind." He further identifies these five 

 primary tentacles of the young larva with the clavicular 

 pieces ^ on the radial axillaries of the adult ; and he copies 

 my figure of the axillary of Pentacrifiics Wyville-Thomsoni to 

 show " dass die Gattung FentacriniLS die primjire mediane 

 Pinnula in recht aufi"alliger Weise bis zum heutigen Tage 

 erhalten hat ^' f- It passes my comprehension altogether how 

 Walther can seriously believe that the delicate tubular ap- 

 pendages of the ambulacral ring in the early larva can be 

 homologous with anti-ambulacral calcareous structures like 

 the jointed pinnules at the side of the arms of the adult, or 

 with the solid clavicular pieces which are parts of the radial 

 axillaries. His theory recalls Hambach's notions about the 

 supplemental pore-plates of Pentremites being the collapsed 

 remnants of '' soft and membranaceous " tentacles like those at 

 the sides of the ambulacra in Echinus, and I cannot imagine 

 that it will ever be accepted by morphologists j but Walther 

 takes these and other scarcely less remarkable statements as 

 the foundation of a long discussion respecting the phylogeny 

 of the Crinoidea, about which I propose to offer some remarks 

 on a future occasion. 



* I believe this name to be due to Schultze (''Monographie derEchino- 

 dermen des Eifler Kalkes," p. 5 (117). 



t Op. cit. p. 183. 



