260 PALEONTOLOGY OF NEW YORK. 



entfernt sich aber clurch das grosse Dorsal septum unci die Ueberdeckung der 

 Stielcffnung doch so sehr von denselben, das ich es nicht gewagt habe, die 

 Form jener Reihe einzufugen. Beide genannten Chara,ktere entfernen unsere 

 Art von den echten Orthis-Arten iiberhaupt, und der letztere, das Pseudodelti- 

 dium auf der Ventral area, spricht f lir ihre Stellung bei Strepiorhijnchus. Dock 

 hat der echte Streptorhynchus ein Pseudodeltidium audi auf der Dorsal area, 

 welches ich bei lepidus vergeblich gesucht habe." 



" Figs. is. K;, 17. Stivptol-hi/nrjais'! li'pi'his. Aricr Iv.vVSElt. 



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.f 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 genei-ic description in the present volume has received the approval of Pro- 

 fessor Kay.skh, atid the name proposeil is in recognition of the emiuont servi<'es of that author in Geolog-ical 

 and Palieontolojjical Science. 



t Deiivinl fr'oni Kayskr's description of the type-si)Ocies. 



