OBOLELLID^. 



601 



Genus BOTSFOE.DIA Matthew, o 



Obolus (Botsfordia) Matthew, 1891, Trans. Roy. Soc. Canada for 1890, 1st ser., vol. 8, sec. 4, No. 6, p. 148. (Merely 



uses the term "Obolus (Botsfordia) pulcher" in the text.) 

 Obolus (Botsfordia) Matthew, 1892, Trans. Roy. Soc. Canada for 1891, 1st ser., vol. 9, sec. 4, No. 5, p. 63. (Merely 



proposed as a new subgenus.) 

 Lingulella Hall and Clarke (in part), 1892, Eleventh Ann. Rept. State Geologist New York for 1891, pp. 232-233. 



(The genus Lingulella is described, Lingulella davisi being given as the type, but Botsfordia cxlata is figured 



as the generic illustration on PI. III.) 

 Lingulella Hall and Clarke (in part), 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, pp. 55-59. (The genus 



Lingulella is described and discussed, but figures of Obolus (Westonia) ella accompany the text, and Botsfordia 



cxlata is figured as the generic illustration on PI. II. Species belonging with other genera are also mentioned as 



belonging to Lingulella.) 

 Mobergia Redlich, 1899, Mem. Geol. Survey India, Paleontologia Indica, new ser., vol. 1, No. 1, Cambrian Fauna 



of the Eastern Salt Range, pp. 5-6. (The description of this new genus is incorporated with that of the new 



species " Mobergia granulata.") 

 Botsfordia Matthew, Waloott, 1908, Smithsonian Misc. Coll., vol. 53, No. 4, PI. XI, and pp. 142 and 145. (Classifi- 

 cation of genus.) ^ 



General form moderately convex, subcircular, with the ventral valve more or less obtusely 

 acuminate and the dorsal valve oval. Ventral valve with the beak (apex) close to the pos- 

 terior margin, perforated with a minute pedicle opening that is separated from the posterior 

 margin by a very short listrium; posterior margin arched above the plane of the side and 

 front margins of the valves. Dorsal valve with a minute beak at the margin. 



Surface with concentric lines and ridges of growth and a more or less regular system of 

 tubercles resting upon concentric, rounded, regular or irregular, separate or inosculating 

 ridges; the tuberculated or granulated surface may cover the entire shell or only a portion 

 of it; the tubercles may be arranged in regular order, as in Botsfordia pulchra (Matthew) (PL 

 LXII), or irregularly, as in B. granulata (Redlich) (PI. LVII). 



The shells are small, rarely exceeding a length of 12 mm. Substance corneous, or phos- 

 phate of lime and chitin. 



Structure of shell lamellated, the inner lamellae being more or less oblique to the outer 

 layer. 



Interior of ventral valve with a small visceral area not exceeding one-half the length of 

 the valve ; the pedicle opening is at the posterior end of the visceral area, where the shell usually 

 has its greatest thickness. Vascular sinuses strong, and well within the body of the valve. 

 Muscle scars arranged essentially as in Oholus; the transmedian and anterior lateral are close 

 to the main vascular sinus and well back toward the posterolateral part of the valve. So 

 far as known, the centrals and the middle and outside laterals are grouped on each side of the 

 front of the visceral area. 



Interior of dorsal valve much like that of AcrotTiele, except that the transmedian muscle 

 scars are separable from the outside and middle lateral scars in one species, Botsfordia gran- 

 ulata (Redlich) ; otherwise they appear to be grouped within the cardinal muscle scar. Median 

 ridge long and prominent; main vascular sinuses well developed and well within the sides 

 of the valve ; visceral area in the adult usually not more than one-half the length of the valve ; 

 central and anterior lateral muscle scars near the center of the valve. 



Tyj^e. — Oholus pulcher Matthew. 



a The sjTionymy far this genus does not .t;ive a complete record of the various frenera under which the species now included in Botsfordia were 

 formerly placed; it gives only those references in which the genus is discussed or described. To complete the record the following mere generic 

 references are listed: _, > 



Oriicula Hall [1847, p. 290]. 



Braohiopode, nouv. gen. [de Vemeuiland Bar- 



rande, 1860, p. 536]. 

 Oioldla (,Orbkula) Ford [1871, p. 33], 

 Obolella Billings [1872a, p. 218]. 

 Lingulella Walcott [1886b. p. 95; 18S7, p. 199]. 

 lingulella? Matthew [1888, p. 28]. 

 Obolus Matthew [1889, p. 306; 1890, p. 151]. 



Lingulella Walcott [1891a, p. 607]. 



Obolus? Hall and Clarke [1892e, pp. 81 and 183]. 



Obolus (Botsfordia) Matthew [1894, p. 90; 1896a, 



p. 115]. 

 Lingulella Matthew [1895a, p. 126]. 

 Acrothele Pompeckj [1896b, p. 603]. 

 Obolus (Lingulella) Walcott [1901, p. 688]. 

 Obolus (Botsfordia) Matthew [1902c, p. 96]. 



