PLATE IV. BRACHIOPODA. 
1. Obolus pristinus, n. sp. a. Ventral valve showing remains of flange 
at the cardinal line. Mag. ? b. Same in profile ce. Mould of 
interior of a ventral (supposed of this species) showing cardinal and lat- 
eral muscle pits and two lateral radiating grooves, also faint impres- 
sions of the central muscles, Mag. 7 d. Same seen from behind. 
e. Mould of interior of a small dorsal valve (supposed of this 
species ) showing pits for cardinal muscle and a crescent within the lat- 
eral muscle scars, also prints which appear to be of the central muscles, 
but are very far back. Mag. ¢. All from 1, 6, 2, Hanford Brook. 
See p. 121. 
2. Trematobolus insignis, Matt. Mag. + a. Interior of the ventral valve 
b. Interior of the dorsal valve c. Dorsal valve seen from he- 
hind ——d. Inside of beak of ventral valve (with hinge area removed). 
Notation of the muscles, &c.: p. a. posterior adductors ; a. d. adjustor 
muscles ; 7. m. lateral muscles ; a. p. anterior depression ; c. p. cardi- 
nal pits ; ¢. cardinal process ; 0. hinge socket; ¢. dentiform process of 
the ventral valve; f. foramen. From Div. 1, }, 2, Hanford Brook. 
See p. 122. 
