34 
PALEONTOLOGY OF NEW YORK. 
The Devonian form, 8. Maia, Hall (= Athyris Maia, Billings), from the Cor- 
niferous limestone, is an excellent representative of this type of structure both 
externally and internally; and the list is completed, so far as our knowledge 
goes, by the addition of S. subumbona, Hall, of the Hamilton group. 
2, Septati. Shells in which dental plates or septa are well developed. 
We are compelled to recognize two groups of the septate Glabrati; 
(a) Martiniopsis, Waagen, 1883. Species with the lamellae developed in 
both valves. 
Waagen has described two species of this genus, M. inflata and M. subpentago- 
nalis, from the Productus limestone of India,* and suggests that this type of 
structure appeared in the Devonian. Beyond the account given by Dr. Waagen 
we know nothing of these fossils. 
(b) (“ Gen. nov.,” Tschernyschew), Type of Martinia semiplana, Waagen. 
Shells with dental lamellae scarcely developed, but with a prominent median 
septum in the pedicle-valve. 
Dr. Tschernyschew has called attention to the peculiar structure of this shell,f 
suggesting the desirability of separating it from its usual association by a distinct 
designation. The species was embraced in the genus Martinia by Waagen, 
who did not observe the presence of the internal septum. Waagen and 
Tschernyschew call attention to the generic similarity of Kutorga’s Spirifer 
corculum with this species, both of which are from the Artinsk-beds, or Permo- 
carboniferous of Russia. 
It seems very doubtful if these forms should be separated from Quenstedt’s 
genus Mentzelia :j; established upon the Spirifer medianus from the Muschelkalk 
of Silesia (Tarnowitz); though Dr. Tschernyschew finds the essential differ¬ 
ence in the presence of dental lamellae in the latter and their absence in the 
Carboniferous species. Quenstedt compares these characters in 8 . medianus to 
those of 8. glaber, saying that they “ bios an der Wand ankleben, und sich nur 
an der Spitze des Loches auf die zierliche dreieckige Querlamelle stiitzen.” 
* Memoirs Geological Survey of India; Productus-limestone Fossils, p. 524. 
t Allgemeine geologische Karte von Russland, Blatt 139 ; Beschreibung des Central-Ui’als und Westab- 
hanges, p. 369, pi. v, figs. 1, 3, 1889. 
I Petrefactenkunde Deutschlands ; Brachiopoden, p. 522, 1871. 
