FROM NORTHWESTERN EUROPE 83 
Somalirhynchia moeschi (Haas) 
(Pl. 8, figs. 1-3, text-fig. 30) 
1890 Rhynchonella trilobata Zieten var. Méschi Haas: 58-59, pl. 7, fig. 7, pl. 8, figs. 1-2. 
1893 Rhynchonella trilobata Zieten var. Moeschi Greppin: 98, pl. 7, figs. 3-4. 
1917 Rhynchonella Moescht Rollier: 174. 
1932 ?Septaliphoria moravica (Uhlig); Wisniewska: 22-24, pl. 5, figs. 3-4. 
1964 Praecyclothyris moescht (Rollier); Makridin: 158-60, pl. 6, fig. 8, pl. 7, fig. 1. 
EMENDED DIAGNOSIS. Medium to large, subpentagonal Somalirhynchia ; mark- 
edly trilobate with about 6-8 ribs on the fold ; septalium present although septalial 
plates relatively weakly developed ; crura radulifer. 
STRATIGRAPHICAL RANGE. Upper Oxfordian ; records, such as those of Haas 
(1890), from the Kimmeridgian are almost certainly the result of misidentifying 
Lacunosella trilobataeformis Wisniewska. The latter species strongly resembles S. 
moeschi externally but can be readily differentiated by its possession of bifurcating 
ribs. 
TYPE SPECIMEN. Lectotype, here selected, the specimen figured by Haas (1890) 
pl. 7, fig. 1; the specimen was obtained from the “‘ Wangener Schichten”’ of 
“ Engelberg bei Olten ”’. 
MATERIAL. 80 specimens collected by Dr. Enay from the “ départements ”’ of 
Jura and Ain. 6 specimens from the collection of the University of Dijon labelled, 
“ Corallien inférieur? ’”’, 7 specimens collected by the author from Pontarlier, near 
Besancon. 
DeEscrRIPTION. External characters. The species has a subpentagonal outline and 
is markedly trilobate. There are between 20 and 30 coarse, simple subangular ribs 
of which 6 to 8 lie on the fold. 
The sharp, suberect beak is flanked by weak beak ridges and these in turn delimit 
the slightly incurved interarea. The deltidial plates, which tend to project slightly 
around the circular, submesothyridid pedicle opening, are conjunct ; however, in 
many specimens the deltidial plates are missing, presumably through having fallen 
out after death, leaving an open delthyrium. 
DIMENSIONS OF FIGURED SPECIMENS. 
length thickness width 
3°57 cm 2:70 cm 3°82 cm 
3°12 cm 2:18 cm 3:00 cm 
Internal characters. Pedicle valve. The lateral cavities are small and limited by 
slender, subparallel, persistent dental lamellae. The delthyrial cavity is quadrate. 
The teeth are crenulated ; lateral denticulae are only weakly developed. 
Brachial valve. A septalium is present ; although the median septum is quite 
strong and persistent, the septalial plates are only weakly developed. The radulifer 
crura have clearly differentiated crural bases. The hinge plates are arched ventrally. 
DisTRiBuTION. The French and Swiss Jura ; ? Poland. 
OCCURRENCE. The specimens collected by the author came from a limestone 
with a typical reef fauna, namely lamellibranchs, terebratulids, gasteropods and 
