368 GENERAL SUMMARY TO 



that a large portion of the last-named valve remains uncovered by the dorsal one. This 

 character I have not observed in any other family or genus except in that of Thecidium. 

 It may therefore be desirable to follow Dr. Waagen while dividing the family Thecideida 

 into two sub-families. Our British Rocks have not hitherto revealed any representative 

 of the Lyttoniince. 



Family— SPIRIFERACEA, Waagen, 1883. 



At p. 135 of my 'Silurian Supplement/ Mr. Glass and myself proposed a new 

 grouping of the spiral-bearing genera, and which, although no doubt liable to improve- 

 ment, seemed to us then, as it still does, to be as nearly natural as we could make it with 

 the material and information in our possession. I need not here recapitulate the nume- 

 rous and very important discoveries effected by the Rev. Norman Glass during his 

 prolonged and able investigations, as they have been fully recorded in my ' Devonian ' 

 and • Silurian Supplements.' To Mr. Whitfield we are likewise indebted for much 

 valuable information and some excellent preparations, which were described and illus- 

 trated by Prof. J. Hall in his large and important work on the ' Palaeontology of New 

 York.' Several successful and some more or less satisfactory efforts in the same direction, 

 all adding to our knowledge, have been effected by W. King, E. Suess, E. Deslongchamps, 

 Zugmayer, Waagen, and others, which have materially added to our knowledge. 



All the genera and species of this great and important family have been shown to be 

 possessed of lamellae spirally coiled in different ways and directions for the support of 

 the labial appendages. In Atrypa, as in Rhynchonella, the fleshy arms were similarly 

 coiled and directed, but in the first-named genus they were supported throughout by a shelly 

 ribbon-shaped and coiled lamella, while none of the species or genera composing the 

 Rhynchonellida had their labial appendages supported by coiled lamellae (see ' Appendix 

 to Supplement,' PI. XXI, fig. 3). The labial appendages in Rhynchonella, as already 

 shown, can be uncoiled to some extent at the will of the animal, but it is very doubtful 

 that this action was possible with any of the Spiriferidce. In their many genera 

 the spirals are connected by a more or less complicated system of the lamellae, and to 

 exhibit these the Rev. Norman Glass, Mr. Whitfield, myself, and some others have 

 devoted much time and labour. 



The spiral coils and connections in Anoploiheca, Sandberger, have not been suffi- 

 ciently worked out in detail. Those of Koninckina have been well described and figured 

 by several palaeontologists ; and Herr Zugmayer has informed me, by letter that, in a 

 large form, named K. quadrata, from the Hallstatt Beds (Etage Norique, according to 

 Mojsisovics), near Hornstein, to the South-west of Vienna, he found the spirals to be 

 free as in K. Leonhardi, and that, in addition to being free, they are double in both 

 species, and composed of a primary coiled lamella and of an accessory one, which last 



