A FOSSIL MARINE DIATOMACEOUS DEPOSIT. 77 



The apparent absence of the characteristic claws or spines at 

 the ends of the horns would place it in Biddulphia ; and there 

 are perhaps better reasons for giving it a genus of its own, but 

 for the present we leave it here. 



Valve resembling in general appearance that of a Hemiaulus, 

 hyaline, produced at the ends into horns which project at right 

 angles to the surface of the valve, and are slightly tapering, 

 with rounded ends. The horns are distinctly cellulate. The 

 most remarkable feature in this little form is the presence of a 

 very long, stout central spine, terminating in a bent claw or 

 fork, by which the spine, projecting from the opposite valve, is 

 clasped : each spine being embraced or clasped by the fork of the 

 contiguous valve. The spines appear to be able to move freely 

 through the forks, so that the valves are sometimes found 

 near together and at others wide apart. Length of valve 

 usually about •001'; length of horns about '001"; length of 

 central spine, '0025'. Scarce. (PL VI., Fig. 17.) 



H. ornifhoeephalus, Grev. — The form mentioned under this 

 name (ante, Part II, p. 11) appears to differ somewhat 

 from Greville's figure. We append figures of valve and frustule. 

 (PL VI., Figs. 18, 19.) 



Anaulus birostratus, Gran. ("VanHeurck Syn.," PL 103, Fig. 

 1). — A small form of this occurs rarely. (PL VI., Fig. 25.) 



Eunotogramma ? ? bivittata, Gran, and Pant. (Pant. " Diat. 

 Hungary," PL 26, Fig. 247). — Valve lunate, long, narrow, 

 tapering, with curved dorsal and ventral margins. Two septa 

 or vittas nearer to the centre than the ends. Surface dotted 

 with scattered granules, which are most numerous at the mar- 

 gins. Not infrequent. (PL VI., Fig. 24.) 



We have figured a normal specimen, but have observed some 

 of much greater length and curvature, .resembling in form 

 Eunotia lunaris. 



Note. — We had named this form Anaulus tenuis, but dis- 

 covering that it had been found in the Hungarian fossil 

 marine deposits, and was published in Herr Pantoczek's work 

 under the name given above, we adopt his nomenclature. 



Terpsinoe americana, Bail., (Ralfs in " Prit.," p. 859). 



Scarce. 



Auliscus pundatus, Grev. (" T. M. S.," Vol. xi., p. 49, PL 3 

 Figs. 15, 16). — A small form, not uncommon. 



