179 



pear on the other lateral half; the proximal margin of the operculum 

 somewhat concave; the avicularian mandible triangular with linear 

 terminal [)art '/'• niamillaris Lamx. 



6) Two opesiulffi of about the same size, both reaching the basal 

 wall; no spine-like processes; the zocecial aperture with a large discoi- 

 dal expansion distallj', and the operculum, furnished with a correspon- 

 ding expansion, has a proximal straight margin; the avicularian man- 

 dible semielliptical with triangular opercular arch T. expansa n. sp. 



5) The proximal margin of the zocecial with a broad and deep sinus: 



7) Proximally to the opesiulse each lateral margin is prolonged into 

 a sharply projecting, thick-walled, semicircular or rounded triangular 

 process, inclining towards the cryptocysl; (the proximal margin of 

 the operculum with a continuous chitinous sclerite; the avicularian 

 mandible triangular, only one opesiular outgrowth reaches the basal 



wall) T. cincta Hutton. 



7) No such processes: 



8) The opesiular outgrowths, of which in most (or all) zocecia only 

 one reaches the basal wall, meet the named wall in closed curved 

 lines; (the avicularian mandible broad, quadrangularly rounded, in the 

 proximal part narrowed; the smallest compasses with almost rectangular 

 opening) T. novae hollandiae Hasw. 



8) Both opesiular outgrowths reach the basal wall, on which they 

 form no closed curved lines: 



9) A short chitinous sclerite on either side of the proximal margin 

 of the operculum, the lateral margins of which are parallel; the avi- 

 cularian mandible narrow, claw-shaped, bent to one side . . 7'. falcifera Hincks. 



9) The proximal margin of the operculum with a continuous chiti- 

 nous sclerite and with lateral margins convergent distally; the avicu- 

 larian mandible has the form of an isosceles triangle; (on the basal 

 surface the two opesiular outgrowths may form sometimes two separate 

 lines, of which one is hook-shaped, sometimes a single continuous, 

 often trapeze-shaped, transverse line; ooccia with pores) T. Uarmeri n. sp. 



Thalamoporella lioticha (Ortmann). 

 Micropora lioticha Ortmann Archiv f. Naturgesch. 56 Jahrg, 1, 1890, pag. 30, 



Taf. II, Fig. 11a— b. 

 (V\. VI, figs. 7a-7p, PI. VI b, fig. 4 a). 

 The ztHL-cia, the length of which is between 0,79 and 0,99'""', have only 

 slightly developed, indistinctly marked and sometimes quite reduced adoral areas, 



VI* 



