80 SUPPLEMENT TO THE 



1. Family — SpiRiFERiDiE, King, 1846 (but much restricted). 



Much difference in opinion has been entertained as to what genera this family should 

 include.^ We would restrict to it the following genera : 



/•I. Spirifera, Sowerhi/, 1815; type Sp. striata, Martin. 

 First Division < 2. Cyrtia, Dalman, 1828; type C. ewporrecta, Dal. 



^3. Syringothyris, Winchell, 1863; type C. cuspidata, Martina 

 S. typa, Winchell, 

 Second Division — 4. Cyrtina, Bav., 1858; type C. heterodyta, Def. 

 Third D"v' ' I ^- ^P'^'^^^^i"^' d'Orh., 1847 ; type S.Walcotti, Sow.^ 



V. 6. Suessia, Deslongchamps, 1854; type 8. imbricata, Desl, 

 Fourth Division — 7. Reticularia, 31' Coy, 1844; type T. imbricata. Sow. 

 The family Spiriferida includes a very large number of species, and much remains to 

 be made clear with respect to their character and grouping ; and it would be very desir- 

 able that some one should undertake a special study of the different species, and prepare 

 a monograph in which they would be grouped according to their natural affinities. 

 Many things have to be considered in the grouping of the SjnriferidcB. It has to be 

 determined whether the shell is fibrous or perforated by canals. The shape and character 

 of the deltidium have to be taken into account, and in this particular some important 

 differences seem to exist between Spirifera proper and Cyrtia. In the first there exists a 

 pseudo-deltidium without any circular foramen, while in Cyrtia and perhaps in Syringo- 

 thyris, the deltidium is convex, covers the entire fissure, and is perforated by a circular 

 foramen, as will be seen illustrated in PI. IX of my ' Silurian Monograph,' Then, again, 

 the shape and character of the septa and shell-structure have to be considered. I am 

 in this respect uncertain whether it is quite correct to retain in the same division 

 Spirifera, Cyrtia, and Syringothyris.^ Spirifera and Cyrtia are known to possess a 

 fibrous imperforated shell, while perforations have been shown by Professor King, 



1 King, in 1846, put into his family Spiriferid/E Spirifer, Atnjpa, Martinia, and Stringoceplialus. 

 In 185U lie added to it AtJiyris, Cleiothyris, Relzia, Deltliyris, Trigonotreta, and Martinia, and excluded 

 Stringoceplialus. 



In 1871 Quenstedt pi-oposed a family DELTHYRiDiE, and arranged his genera in two divisions : 



a. Spirifer, Ctioristites, Cyrtia, Trigonotreta. 



h. Spiri/erina, Syritigottiyris, Cyrtina, Suessia. 

 Phillips, in 1841, placed in the family Delthyrid^ Orthis, Spirifer, Stringoceplialus, Pentamerus, 

 Cleiothyris (a strange mixture of completely different and distinct genera). 



Other authors have proposed different arrangements, but these need not be here recorded, 



2 By the means of very diluted acid M. Munier-Chalmas, of the Sorbonne, Paris, has been able 

 to dissolve the entire matrix filling Spiriferina rostruta and other species so as to show the spirals and 

 their connections completely and as perfectly as if the shell had just been taken from the Jurassic sea, 



^ King, "Notes on some Perforated Palaeozoic Spiriferidse," ' Geol. Mag,,' vol. iv, p. 351, 1807. 



