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PALAEONTOLOGY OF NEW YORK. 
entfernt sich aber durch das grosse Dorsal septum und die Ueberdeckung der 
Stieloffnung doch so sehr von denselben, das ich es nicht gewagt habe, die 
Form jener Reihe einzufiigen. Beide genannten Charaktere entfernen unsere 
Art von den echten Orthis-Arten iiberhaupt, und der letztere, das Pseudodelti- 
dium auf der Ventral area, spricht fiir ihre Stellung bei Streptorhynchus. Doch 
hat der echte Streptorhynchus ein Pseudodeltidium auch auf der Dorsal area, 
welches ich bei lepidus vergeblich gesucht habe.” 
; Figs. 15, 16, 17. Streptorhynchus ? lepuhis . After Kayser. 
Though represented by only a single known species the form is an important 
one in the series of streptorhynchoid genera and it is therefore separated under 
the name above proposed.* 
Diagnosis.! Shell subsemicircular; hinge-line nearly equaling in length the 
greatest width of the shell; convexity normal. Pedicle-valve more convex 
than the brachial; area moderately high; delthyrium covered by a convex 
plate. Brachial valve slightly convex; area narrow; delthyrium covered. 
In the interior, a large, triangular median septum extends almost to the bot¬ 
tom of the opposite valve. Surface with a slight median ridge and furrow 
on brachial and pedicle-valves respectively; covered with sharp plications, 
increasing by intercalation near the margin. 
Shell-substance punctate. 
Type, Orthis lepida , Schnur. A somewhat rare species in the “ Crinoiden- 
schichten” of the Middle Devonian at Pelm and Gerolstein. 
* The publication of this generic description in the present volume has received the approval of Pro¬ 
fessor Kayser, and the name proposed is in recognition of the eminent services of that author in Geological 
and Palaeontological Science. 
f Derived from Kayser’s description of the type-species. 
