BRACmOPODA. 85 



Genus SPONDYLOBOLUS, McCoy. 1852. 



1852. SpondyloboltiS, McCoy. Annals and Magazine Natni'al History, vol. viii, p. 407. 



1SS3. Spondyloholus, Davidson. Introd. Brit. Foss. Brachiopoda, j). 125 ; pi. ix, figs. 241-243. 



1855. 8po7iclylohohiJi, McCoy. British Palteozoic Fossils, p. 255, pi. 1 H, figs. 4, 5. 



Types, Crania Sedgwicki, Lewis, C. craniolaris, McCoy. Lower Llandeilo. 



(The former species is not considered a Brachiopod by Mr. Davidson ; vide 

 Silurian Brachiopoda, p. 83, pi. viii, fig. 25.) 



Very little is known of this genus except from the original description given 

 by McCoy, and the figures subsequently produced in the " British Palaeozoic 

 Fossils, p. 255, pi. I h, figs. 4, 5. Mr. Davidson, from the first, expressed his 

 doubt of its generic value, but he has reproduced the original figures in both 

 the places cited. In the latter* he promises a further reference and explana- 

 tion of the fossil. We have not, however, been able to find anything of later 

 date, further than a casual mention of the name,f and even the species does 

 not appear in any of his various lists and indexes. 



McCoy's diagnosis of the genus is as follows: 



" Subcircular, slightly narrowed towards the indis- 

 tinct, short hinge-line, nearly equivalve, flattened. 

 Small valve with a slightly excentric apex ; beneath 

 which, on the interior, the substance of the valve is 

 thickened into a wide, undefined boss. Opposite valve fig. 4i. spondyioioius cmnwiaHs 

 slightly longer, from the apex being perfectly mar- 

 ginal and slightly produced, channeled by a narrow, triangular groove below, 

 the anterior end of which is flanked by two very prominent thick, conical, 

 shelly bosses, representing hinge-teeth ; substance of the valve thick, testace- 

 ous, not glossy, minutely fibrous, but not distinctly punctated under a lens of 

 moderate power, except by the ends of these fibres." 



With our imperfect knowledge of this fossil, little can be said further than 

 to suggest its general obolelloid appearance, and the possibility that its cardinal 

 bosses may indicate a similar relation between it and Obolella as is found to 

 exist between the species of the genus Baeroisella and the true Lingulas. 



* Expl. pi. viii, figs. 26, 27. 



t Genei-al Summary, 1884. p. 352. 



