sd ANIMALS. 125 
clusion, I have seen punctures in species of every genus of Spiriferide, so that I am led 
to conclude a punctated structure characterised the entire family." The only difference 
prevailing as regards the punctures, is in their size: in Zrigonotreta Walcott they are 
large; in 7. undulata they are extremely small; and in Spirifer heteroclytus they are 
intermediate im size. 
The proximate affinities of Sprrzferid@ have not as yet been satisfactorily determined ; 
their spiral labial appendages associate them with Hypothyride ; but to which genus 
of this family they are immediately related, is far from being sufficiently clear. 
Isorhynchus, concluding from the form of some of its species, offers the nearest 
approach to certain Silurian Trigonotretas, notably the 7. MJarklini (Spirifer, id.) of 
De Verneuil. ; 
Spiriferide were very abundant during the primary period; but at its close, 
particularly in the Permian division, they appear to have decreased considerably as 
regards numerical amount of species, though not in the same respect in genera; 
since four or more groups of this kind, viz., Zrigonotreta, Cleiothyris, Martina, and 
probably Spirifer,’ were then in existence. During the secondary period only two 
genera, represented by the Trias Zrigonotreta fragilis, including the Jurassic species, 
and a Martina (vide postea) are known to have been living. 
Our next step will be to notice the various genera included in the present family 
as given in the Synoptical Table. 
Genus Spirifer, J. Sowerby, 1815 (= Cyrtia, Dalman, 1827). 
This genus is typified by the Anomites cuspidatus of Martin—a remarkably inequi- 
valved shell; with an elevated area; an upright pedicleiferous umbone; and having, 
according to M. Deshayes, the fissure closed in all its extent with a deltidium furnished 
towards its apex with an oval-shaped foramen.’ 
1 The punctures are best seen by candle-light, with a Stanhope lens. In looking for punctures, 
Trigonotreta Waleotti should be examined first: in the split laminz of this species the punctures are seen 
intersecting the capillary fibres, both of which are large compared with what they are in those species in 
which they are generally considered to be absent. 
* From the description which Count Keyserling gives of his Spirifer Schrenki (vide Reise in das Petchora- 
Land, p. 234) found in the Permian limestone of Petchora, I am disposed to conclude that it is a true 
Spirifer. 
5 «Posée sur sa valye supérieure cette coquille a la forme d’une pyramide triangulaire dont la plus 
grande surface, la seule qui soit plane, est formée par le crochet tout-a-fait droit de la grande valve ; cette 
surface est traversée dans toute sa hauteur par une gouttiére triangulaire; si la matiere dure de la couche 
qui la remplit ordinairement a été enlevée, on trouve cette goutticre fermée dans presque toute son ¢tendue, 
et offrant, vers le sommet, un trou ovalaire, de sorte que cette coquille, malgre l’étrangeté de sa forme, a en 
effet les caractéres des Térébratules.”’ (Animaux sans Vertébres, 2”° Ed., vol. vii, p. 368, 1836.) 
