BRITISH AVONIAN CONODONT FAUNAS 133 
Genus LIGONODINA Ulrich & Bassler 1926 
1925 Ligonodina Bassler : 218 (nom. nud.). 
1926 Ligonodina Ulrich & Bassler: 12, 13. 
Type spEcIES. Ligonodina pectinata Ulrich & Bassler 1926. 
Ligonodina beata nom. nov. 
Plate 26, figs. 4-6b 
1934 Ligenodina delicata Branson & Mehl: 199, Pl. 14, figs. 22, 23. 
1934 Ligonodina delicata Branson & Mehl; E. R. Branson : 328, Pl. 27, fig. 3. 
1934 Ligonodina sp. Huddle: 62, Pl. 12, fig. 8. 
1939 Ligonodina delicatula Cooper : 390, Pl. 45, figs. 50, 60, 61. 
1943 Ligonodina tenerva Cooper & Sloss : 174, Pl. 29, fig. 34. 
1944 Ligonodina delicata Branson & Mehl; Branson & Mehl im Shimer & Shrock: 241, 
Pl. 93, fig. 74. 
non 1944 Ligonodina delicata Branson & Mehl ; E. B. Branson : Pl. 26, fig. 23, (=Palmatolepis 
Sp). 
1947 Ligonodina delicata Branson & Mehl ; Miller & Youngquist : 509, 510, Pl. 73, fig. 12. 
1949 Ligonodina delicata Branson & Mehl ; Thomas: 408, 411, Pl. 4, fig. 22. 
non 1949 Ligonodina delicata ? Branson & Mehl ; Thomas: PI. 3, fig. 41, (=Ligonodina sp.). 
non 1964 Ligonodina delicata Branson & Mehl; Bergstr6m: 28, text-fig. 12. Bergstrém 
(1964, 28) has demonstrated that Phvagmodus delicatus Branson & Mehl, 1933, 123, 
Pl. 10, fig. 22) should be regarded as a species of Ligonodina. The name for this 
species, therefore, has precedence over that of Ligonodina delicata Branson & Mehl 
(1934, 199) and the latter species becomes a junior homonym of the former. In 
this case, it is necessary to select a new name, and we have selected the name 
Ligonodina beata. The holotype is University of Missouri Catalogue No. C. 243-4 
(Branson & Mehl 1934 : 199). 
non 1964 Ligonodina delicata Branson & Mehl ; Budurov & Tschurner: PI. V, figs. 23a, b. 
MATERIAL. 361 specimens : figured, X 202, X 203, X 2oI. 
Rance. North Crop KL 19-ZLA 21, Avon Gorge K 3-C 25. 
Description. A fragile unit with a slender main denticle which has a sub-circular 
cross-section. The main denticle is recurved posteriorly at 45°. The anterior- 
aboral process originates immediately anterior to the main denticle, and commonly 
bears 3 or 4 isolated, discrete, sub-circular denticles, which are posteriorly inclined. 
The posterior bar is fairly long and rarely preserved. It bears up to 6 isolated 
laterally compressed denticles, which are posteriorly inclined, and tend to increase in 
size posteriorly. 
In aboral view, the anterior portion of the posterior bar is excavated, the deepest 
excavation being beneath the main denticle ; the cavity extends inverted beneath 
the anterior aboral process. The cavity is grooved, the groove running some way 
along the posterior bar and the complete length of the anterior aboral process. 
REMARKS. Our specimens agree very closely to the holotype described by Branson 
& Mehl. 
