628 CAMBRIAN BRACHIOPODA. 



Formation and LOCALirr.a — Ordovician: (336w) Near Pawlowsk, near St. Petersburg, Russia. 



Drift bowlders of Echinosphxrites limestone at the following localities: (3861) Near Wehlau, 30 miles (48.3 km.) 

 east of Konigsberg, East Prussia; (386k) near Wormditt, East Prussia; and (386 1) near Marienwerder, West Prussia; 

 all in Germany. 



Passage beds between the Upper Cambrian and the Ordovician: (336e) Orthoceratite limestone at Pulkowa; 

 (337m) Orthoceratite limestone at Popowka; and (336y) glauconitic limestone at Popowka; all near St. Petersbm'g, Russia. 



(337f) "Vaginatenkalk"6 at Tiirsel, 15 miles (24.2 km.) west of Narwa; and (337g) " Vaginatenkalk " 6 at Chudleigh, 

 25 miles (40 km.) west of Narwa; both in the Government of Esthonia, Russia. 



Genus KEYSERLINGIA Pander, c 



Orbicula de Verneuil (in part) [not Lamarck], 1845, G^ologie de la Russie d'Europe, by Miirchison, de Vemeuil, 

 and de Keyserling, vol. 2, pt. 3, p. 288. (Described and discussed in French. Of the species included in the 

 genus only "Orhicula buchii" is treated in this monograph.) 



Not Orhicella Dana, 1846; see Scudder's Nomenclator Zoologicus, p. 236. (Proposed for a genus of the Polypi.) 



Orbieella d'Obbigny (in part) [not Dana], 1850, Prodrome de Pal^ontologie, vol. 1, p. 20. (Characterized in French. 

 "Orhicella buchi " is the only one of the many species placed under the genus which is treated in this monograph.) 



Keyserlingia Pander, 1861, Bull. Acad. imp. sci. St.-P6tersbourg, tome 3, columns 46-48. (Described and discussed 

 in German.) 



Keyserlingia Pander, Dail, 1877, Bull. U. S. Nat. Mus. No. 8, p. 39. (Merely listed, but gives "Orbicula reversa" aa 

 the type.) 



Orbieella d'Orbigny, Dall (in pai-t), 1877, idem, p. 50. (Cites Orbieella buchi as the type and gives synonymy of genus.) 



Keyserlingia Pander, Oehleet, 1887, Manuel de conchyUologie, by Fischer, p. 1263. (Described in French, with 

 figures of Keyserlingia buchi.) 



Not Keyserlingia Karpinsky, 1887, Bull. Acad. imp. sci. St.-P6tersbourg, tome 31, p. 476, footnote. (The use of the 

 name Keyserlingia in this reference is clearly a typographical error, " Helmersenia" being the proper term.) 



Orbieella d'Orbigny, Hall and Clarke, 1892, Eleventh Ann. Rept. State Geologist New York for 1891, p. 254. (Pan- 

 der's original description, 1861, p. 46, translated.) 



Orbieella d'Orbigny, Hall and Clarke, 1892, Forty-fifth Ann. Rept. New York State Museum for 1891, p. 570. (Copy 

 of preceding reference.) 



Keyserlingia Pander, Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, pp. 117-119. (Copies 

 - the translation of Pander's original description given by Hall and Clai-ke, 1892a, p. 254, and discusses the genus 

 and the priority of the generic names proposed for it.) 



Keyserlingia Pander, Walcott, 1908, Smithsonian Misc. CoU., vol. 53, No. 4, PI. XI, and pp. 142 and 146. (Classifica- 

 tion of genus.) 



The description of the type species, Keyserlingia hucM, gives all that is known of this genus. 

 My description and remarks are based on the study of a considerable number of specimens 

 collected for me by Mr. Schmalensee at Jaggowal, Esthonia, and a few received from Dr. Fr. 

 Schmidt, collected at Kunitz, Government of Pskow. 



From the means of comparison with other related generic forms it appears that Keyser- 

 lingia has an interior pedicle tube somewhat like that of Siflionotreta unguiculata (Eichwald), 

 but that the pedicle cleft is back of the apex as in Schizotreta elliptica Kutorga. A young shell 

 has a very clear openmg in the pedicle cleft, but in nearly all adult shells the opening is closed. 

 In the interior of the ventral valve of many shells the pedicle tube extends forward into the 

 valve (PI. LXXXI, fig. 4a), but in adult shells it is often closed by a vesicular growth of shell 

 (fig. 4b). 



Keyserlingia, as exemplified by K. hucJii, is a form having an external pedicle cleft back 

 of the apex much like that of Schizotreta, and an interior pedicle tube extending forward a 

 varying distance but not usually beyond the center. 



Type. — Orhicula hucJii de Verneuil. 



The generic name was given in honor of A. de Keyserling. 



^ Keyserlingia BUCHI (de Verneuil). 

 Plate LXXXI, figures 4, 4a-e. 



Orbicula buchii de Verneuil, 1845, Geologic de la Russie d'Europe, by Murchison, de Vemeuil, and de Keyserling, 

 vol. 2, pt. 3, pp. 288-289, PI. XIX, figs. la-c. (Described and discussed in French as a new species.) 



a Localities 336y and 337m are represented in the United States National Museum collections; the other localities are taken from the 

 references in the s.vnonymy. The authority for each of the localities cited will be found in the list of localities, pp. 161-291. I have been 

 unable to determine which is the type locality. 



6 The Vaginoccras limestone is the equivalent of the Orthoceratite limestone. 



c The synonomy for this genus is not complete; it includes only those references dealing with the species taken up in this monograph. 



