Manchester Memoirs, Vol. Ixii. (19 17) 107 



horizontal whorl surrounding the primordial cell consists of 

 six chambers. The arrangement of the chambers cannot be 

 seen in unabraded specimens owing to the opacity and smooth- 

 ness of the exterior surface of the test. The perforations of 

 the central horizontal laminae are irregularly disposed and so 

 are* the vertical connecting columns. 



Fig. 6, Plate VI, shows well the transverse section of the 

 cortical chambers. Fig. 7, Plate VIII, the longitudinal section 

 of the same, as well as the construction of the shell-matter 

 occupying the interior of the hollow cone formed by those 

 chambers. 



I would wish to remark that the drawings given here are 

 made from actual specimens and are in no sense reconstruc- 

 tions. 



(Halkyard's species is represented in the collection by 

 specimens on the type slides and by a balsam mount containing 

 three vertical sections taken in different planes. The available 

 specimens therefore are sufficient, in connection with his draw- 

 ings, to connect the species with Chapmania gassinensis, 

 Silvestri. The measurements, size and shape of the chamberlets 

 all agree fairly closely with that form. The species has been 

 thoroughly analysed and discussed (together with its isomorph 

 Dictyoconus cegyptiensis) by Silvestri in the Rivista Italiana di 

 Paleontologica (Ann. XI, 1905, Pt. Ill, pp. 113-120, pi. II.) 



Halkyard's forms appear to be more bluntly conical than 

 Silvestri's, and the basal edge in consequence less acutely angu- 

 lar. It will be observed that Flalkyard gives as locality for his 

 specimens "material collected from sandy and shelly veins in 

 the beds exposed between tide-marks." This does not alto- 

 gether exclude the possibility of their being derived fossils 

 washed from some earlier or later horizons than the other 

 Biarrilz specimens, and a note among the Halkyard MSS. 

 shows that he inclined to this opinion himself.) 



[HALKYARDIA, GEN. NOV.] 



Genus Ltnderina, Schlumberger. 



"Test discoidal, thickened at the centre, composed of a 

 single rank of numerous little chambers disposed circularly 

 round a central chamber and in the same plane. The walls 

 of each chamber are prolonged towards the middle above the 

 chambers already formed. This calcareous envelope is traversed 

 by large perforations which penetrate directly to the internal 

 chambers." 



