BIDDULPHIA. 473 



B. Baileyii W. Sm. (S.B.D., ii., p. 50, pi. 62, f. 322 ; Zygoceros 



mobilicnsis Bail. ; H.V.H. Atl., pi. 10 1, f. 4-6*), plate 20, fig. 636. 



A delicate, very imperfectly silicious diatom. Valve broadly lanceolate, 

 bearing two spines alternating with the terminal processes, and situated at the 

 lower and upper third near the longitudinal axis of the valve ; puncta in 

 quincunx very delicate, about 12 to 14 striae in 1 c.d.m. Girdle face showing 

 the valve portion with centre flat or concave, the conical terminal processes 

 completely punctate, with truncate, somewhat capitate, ends, they and the spines 

 very long, somewhat bifurcated at the apex, each being borne on a small 

 elevation of the valve. Connecting membrane with puncta in quincunx, 

 excessively delicate, about 18 striae in 1 c.d.m. Length of valve, 7 to 16 

 c.d.m. 



Marine. Blankenberghe (H.V.H.), England (W. Sm., Williamson, Kitton, Stolt., Norman, 

 Comber), Ireland (O'Meara), 



B. granulata Roper (T.M.S., 1859, vii., p. 13, pi. 1, f. io-u, pi. 



ii., f. 12 ; H.V.H. All., pi. 99, f. 7 and 8, and pi. 101, f. 4*. In the latter figure 

 the general outline is very exact, but in the fair copy of the drawing the small 

 spines on the valve have been accidentally omitted; Type No. 492), plate 

 20, fig. 637. 



Valve ellipticdanceolate, bearing two very long spines alternate with the 

 terminal processes, approximate to them and to the longitudinal axis of the 

 valve ; striated in quincunx (about 13 or 14 in i c.d.m.), and bearing numerous 

 small awl-shaped spines, about 4 in 1 c.d.m., placed in irregular lines. Girdle 

 face quadrangular, showing the valve portion with the centre fiat or concave, 

 the processes inflated, then abruptly attenuate on the external side, punctate 

 up to the apex, which is somewhat rounded, and the spines very long, often 

 flexed at an obtuse angle near their middle. Connecting zone with puncta 

 in quincunx, with 14 stria? in 1 c.d.m. Length of valve, 5 to 8 c.d.m. 

 (in the specimens observed). 



Marine. Very rare. Antwerp (Scheldt), Blankenberghe, England (Coll. W. Arnott !, Comber, 

 Stolt., Norman). 



B. turgida W. Sm. (S.B.D., ii., p. 50, pi. 62, f. 38; Cerataulus 

 turgida Ehr.; H.V.H. Atl., pi. 104, f. 1 and 2* ; Type No. 495), plate 21, 

 fig. 638. 



Valve varying from a round to a longly elliptic form ; sometimes furnished 

 near the margin with a circlet of very short spines, bearing diagonally two 

 broad truncate processes and two stout spines ; striae undulate, 9 in 1 c.d.m., 



