LAGENA ANNECTENS. 203 



21. Lagena annectens, sp. nov., Burrows and Holland. Plate VII, figs. 11 a, b. 



Lagena l2evigata, pars, Beuss, 1870. Sitz. k. Ak. Wiss. Wien, vol. lxii, p. 16. 

 Fissueina, No. 75, Schlickt, 1870. Pietzpuhl, p. 13, pi. v, figs. 7—9. 

 Lagena quadricostulata, pars, Brady (non Beuss), 1881. Eeport ' Challenger,' 



p. 486, pi. lix, fig. 15. 



Characters. — Test pyriforrn, compressed, entosolenian, aperture fissurine; 

 periphery carinate or non-carinate, sometimes notched at the aboral extremity. 

 Each face of the test ornamented with two narrow curved surface-markings or 

 shallow sulci, parallel with the margins, and occasionally uniting in a horse- 

 shoe form. 



This species at first sight bears a strong resemblance to L. quadricostulata, 

 Reuss ; but the ornamentation consists not of arched costulse, as in the latter 

 species, but of marks apparently due to a structural difference in the shell- 

 substance along the lines of the curves on the surface. In recent and some 

 fossil specimens, where the test is clear and glassy, the markings have the 

 appearance of frosted bands. This is well shown in Schlicht's figures quoted 

 above, and in several of the ' Challenger ' specimens which are preserved in the 

 British Museum, and which Ave have carefully examined. It is possible that this 

 effect is produced by minute tubuli in the shell-walls ; but we have as yet been 

 unable satisfactorily to determine this point. In fossil specimens the "frosted" 

 bands are sometimes replaced by shallow sulci, probably due to an erosion of the 

 shell-substance alono- the line of the bands. 



Lagena annectens must not be confounded with L. lucida, Williamson. The 

 general contour of the shells differs considerably, L. annectens being more robustly 

 built. Moreover, the "milky white" horseshoe-shaped bands in L. lucida occupy 

 a much greater relative proportion of the shell surface, and the internal tube, so 

 strikingly apparent in L. lucida, is hardly, if at all, developed in any of our 

 specimens of L. annectens, recent or fossil. 



Occurrence. — The ' Challenger ' specimens were obtained off Kerguelen Island 

 (20 to 120 fathoms), and off Sydney (410 fathoms). Schlicht's specimens, described 

 by Reuss, were from the Oligocene of Pietzpuhl. The Crag specimen is from 

 Tattingstone, zone d. 



27 



