26 JURASSIC RHYNCHONELLIDS 
Monticlarella strioplicata (Quenstedt) 
(Pl. 1, figs. 8-10, text-fig. 11) 
1852 Tevebrvatula strioplicata Quenstedt: 455, pl. 26, fig. 23. 
1858 Tevebratula strioplicata Quenstedt: 635, pl. 78, fig. 24. 
1871 Tevebrvatula strioplicata Quenstedt: 132, pl. 40, figs. 24-32. 
1885 Terebratula strioplicata Quenstedt: 694, pl. 53, fig. 59. 
1909 Rhynchonella strioplicata (Quenstedt); Simionescu: 40, 41, 94, pl. 7, fig. 18. 
1913 Rhynchonella strioplicata (Quenstedt); Jacob and Fallot: 17. 
1917. Rhynchonella strioplicata (Quenstedt); Rollier: 123. 
1917. Rhynchonella strioplanata (Quenstedt) ; Rollier: 123. 
1917 Rhynchonella pauciplicata Rollier: 123. 
1917 Rhynchonella tenuiplicata Rollier: 123. 
1917. Rhynchonella furcatella Rollier: 123. 
1932 Monticlarella strioplicata (Quenstedt); Wisniewska: 60-62, pl. 6, figs. 1-7, text-fig. 18. 
EMENDED DIAGNOsIs. Medium sized,:subpentagonal to slightly elongate Monti- 
clarella ; rectimarginate or with a low uniplication ; ornament of fine striae poster- 
iorly passing anteriorly into short coarse ribs ; crura arcuifer. 
STRATIGRAPHICAL RANGE. Oxfordian—Kimmeridgian—Lower Volgian ; ¢tvans- 
versarium to Gravesia zones. 
TYPE SPECIMEN. Lectotype, here designated, fig. 25, pl. 40 of Quenstedt (1871) 
from the ““Malm gamma ”’ of Lochen, Germany. 
MATERIAL. II specimens from the collection of the University of Ttbingen ; 
22 collected by the author from Swabia and Franconia. i 
DeEscrRIPTION. External characters. The shell is biconvex with the pedicle valve 
slightly more inflated than the brachial. The beak is small, sharply pointed and 
erect. The oval, hypothyridid pedicle opening is small and is flanked by two small, 
discrete deltidial plates. Beak ridges and interarea are only poorly developed. 
Posteriorly the ornament consists of very fine striae, while on the anterior half or 
third of the shell are developed five or six relatively coarse ribs. The fine striae 
continue to the anterior of the shell only in the troughs between the ribs. The 
outline varies from subpentagonal to suboval, specimens having the former shape 
being wider and having more ribs ; the length is usually greater than the width. 
There appears to be a complete gradation between the two forms at all stratigraphical 
levels for which there is material available ; however, the material is relatively 
limited and it is not possible to say whether the proportions of the two forms change 
or have any stratigraphical value. 
DIMENSIONS OF FIGURED SPECIMENS. 
length thickness width 
1°18 cm 0-80 cm I'-I3 cm 
I-04 cm 0-68 cm 0-98 cm 
I-05 cm 0-70 cm 0-78 cm 
Internal characters. Pedicle valve. Dental lamellae are present but only poorly 
developed and attached to the shell wall only at their posterior extremities. The 
teeth are strong. 
