FROM NORTHWESTERN EUROPE 73 
ECHINIRHYNCHIA subgen. nov. 
NAME. Latin echinus-im, the sea urchin : the shell of Echinirhynchia is covered 
with spines. 
Type species. Terebratulites senticosus Schlotheim (1820). 
DiAGnosis. Small to medium sized species of Acanthorhynchia ; usually sub- 
triangular in outline ; valves equally biconvex or with a flattened brachial and more 
inflated pedicle valve ; beak small and either adpressed to the brachial valve or 
suberect ; deltidial plates reduced or absent ; when the beak is suberect there is an 
open triangular delthyrium ; no dental lamellae or septalium ; anterior commissure 
rectimarginate. 
STRATIGRAPHICAL RANGE. Oxfordian to Lower Volgian: mariae—Gravesia 
zones. 
DISTRIBUTION. The subgenus appears, from the literature, to be restricted to the 
Jura, ranging from the southern French Jura through Switzerland to the Franconian 
Alb north of Erlangen ; the only records outside this area are of A. (Echinirhynchia) 
fileyensis (Buckman & Walker) from the Lower Calcareous Grit of Filey Brigg, 
Yorkshire, and of “ Acanthorhynchia aff. senticosa (Schlotheim) ’’ from Rumania 
(Patrulius, 1964). 
REMARKS. The three species included are the only ones of which sufficient 
material has been obtained to allow description. Several nominal species, such as 
Terebratula senticosa impressae Quenstedt and T. senticosa y alba Quenstedt, 
almost certainly belong within the subgenus but the author has not been able to 
evaluate their position. The Quenstedt species mentioned above are the only ones 
recorded from the Swabian Alb area, although some of Oppel’s records of Rhyn- 
chonella spinulosa probably included material referable to Echinirhynchia. 
A. (Echinirhynchia) senticosa (Schlotheim) 
(Pl. 7, figs. 1-3, text-fig. 26 (top)) 
1820 Tevebrvatulites senticosus Schlotheim: 268. 
1834 Terebratula senticosa Buch: 59-60. 
1838 Terebrvatula senticosa Buch: 162-63, pl. 16, fig. 5. 
1858 Tevebvatula senticosa Quenstedt: 457. 
1871 Tevebvatula senticosa silicea Quenstedt: 115, pl. 39, fig. 66. 
1886 hynchonella senticosa (Schlotheim); Rothpletz: 93, 156-57, pl. 15, figs. 4-9. 
1889 Acanthothyris senticosa (Schlotheim); Buckman and Walker, 55-56. 
1917 Acanthothyris senticosa (Schlotheim); Rollier: 80. 
1918 Acanthorhynchia senticosa (Buch); Buckman, 7o. 
EMENDED DIAGNOSIS. Small to medium sized, pyriform Echinirhynchia ; test 
covered with numerous fine, spinose ribs ; beak relatively large and suberect to 
erect ; deltidial plates absent resulting in an open triangular delthyrium ; recti- 
STRATIGRAPHICAL RANGE. Kimmeridgian—Lower Volgian : pseudomutabilis to 
Gravesia zones. 
