322 ^Ir. J. W. Salter on some nevj Pahiozoic Star-Jishes. 



but with moveable body-segments. There are also new Encri- 

 nites and Bryozoa, and abundance of the common Graptolite 

 and shells of the Lower Ludlow rock. 



The Star-fish in this locality therefore occupy nearly the same 

 geological horizon as those found by Prof. Sedgwick in West- 

 moreland, viz. the upper portion of the Lower Ludlow rock ; 

 and one of them, the Uraster primcevus of Forbes, is identical 

 with a Kendal species. 



Besides these Upper Silurian species, Prof. Forbes had one 

 other from the Lower Silurian rocks of Wales. Another is now 

 added, which fortunately supplies parts not observable in the 

 species described by our late friend ; and while these were being 

 examined, a third was found among some rubbishy specimens 

 from the Upper Caradoc or Pentamerus beds of the Malverns. 

 They will be described first, as probably nearest to the living 

 forms. 



The species referred by Forbes to Uraster were not perfect 

 enough for him to see whether they possessed more than a 

 double row of suckers in each ambulacral avenue, and the general 

 form — the reticular skeleton (above) and the tufts of short spines 

 — resembled much the corresponding parts in that genus. But 

 the specimens now at command are much more complete, and 

 show that there were not more than two rows of hollows for 

 suckers ; while the other characters of the skeleton, particularly 

 the row of great submarginal or rather adambulacral plates, are 

 quite incompatible with the Vrasterue. 



The excessive shallowness of the ambulacra in most of the 

 species, and the square plate-like form of the ambulacral ossicles, 

 render two out of the five genera to be noticed unlike any of 

 the modern forms ; but in others there is a greater depth in the 

 grooves, and the ossicles themselves are longer and narrower, and 

 more of the ordinary type. This is the case with Palasterina 

 primeBva {Uraster, Forbes) (PI. IX. fig. 2), the first-described of 

 the British species ; and the analogy of the pentagonal-plated, 

 thin disk of this species with the Asteriscus (or Asterina) roseus 

 is sufficiently close to induce a further comparison, and was 

 indeed first suggested by Prof. M'Coy (Synops. Woodw. Mus. 

 Fase. 1, 1851). 



After examination of all the accessible forms of AsteriadcE in 

 the British Museum, or those figured in Miiller^s work, no better 

 affinity than this could be found for the whole group — from 

 Palaaster (PL IX. ^S. I), which in its thick and rounded arms 

 closelv resembles those species of Asteriscus called Patiria by 

 Gray,* to the extreme form of Palaocoma (fig. 3), in which the 

 bordei'ing spines are of enormous length compared with the size 

 of the Star-fish. This latter form finds, I think, its nearest 



