Sedgwick Museum Notes ; Notes on the Genus 

 Sphaerocoryphe. 



By W. B. R. King, M.A., F.G.S. 

 (PLATE XIII.) 



T^R. F. R. COWPER REED, in a paper entitled " Notes on the 

 -^ Affinities of tlie Genera of the Cheirviridse 'V points ont that 

 S}jhceroconj23lie belongs to tlie Cheiruridse, while Staurocephahis, 

 which has at first sight some superficial likeness to it, belongs 

 probably to the Encrinuridiae. 



Some additional light has been thrown on to this subject by the 

 recent discovery of a complete specimen of Sphceroco^pJie in the 

 Ashgillian beds of Norber Brow, Austwick, near Settle, by Mr. T. H. 

 Thorney croft, of Pembroke College, Cambridge. Mr. Thorn ey croft 

 has kindly presented the specimen to the Sedgwick Museum. The 

 specimen, which is referable to Sphcerocoryphe tJiomsoni Reed, 

 although somewhat compressed and crushed laterally by the cleavage, 

 possesses all the characteristics of the species, but the chief point 

 of interest is that the hypostome is preserved in place, and was 

 found inside the swollen frontal part of the glabella. The hypostome 

 and material filling the glabella broke away and remained on the 

 " cast " side of the specimen. This appears to be the first hypostome 

 definitely referable to a specimen of this genus. The hypostome of 

 Staiirocephalus is also rare, but one is figured by Salter,^ and this is 

 preserved in the British Museum. 



Novak ^ has shown that hypostomes are of considerable use in 

 determining the family relationship of various genera, and his 

 ' contention seems to hold good in this case also. It may be as 

 well, therefore, to describe the hypostome of Sjyhcerocoryjjhe thomsoni 

 which Mr. Thorneycroft found associated with the complete in- 

 dividual and conij^are it with that of other Cheirurids and 

 Staurocephalus. 



The hypostome is sHghtly smaller than the swollen frontal part of 

 the glabella, since it was found pushed into it without contortion. 

 The general outline is square, formed of a large central, raised, 

 elliptical portion, surrounded by a deep wide groove and raised 

 narrow margin. The anterior margin is not well preserved in 

 this specimen, but appears to be slightly curried in outline and to 



1 Geol. Mag., 1898, pp. 206-14. 



2 " British Trilohites " : PalcTont. Soc, 186-1-83, pi. vii, fig. 17. 



^ Ottomar Novak, " Stiidien an Hj^postomen boiimischer Trilobiten " : 

 Kon. Bolim. Geseliscliaft der Wissenschaften, Prag, 1879-86. 



