160 



and with at least two pear-shaped perforations. Independent hut no dependent 

 (wicnhiria may appeal'. The frontal shield with [)ores. 



dr. figtilaris. Cr. pliiloinela i>. uniuda and Cr. clilhridiaUt ' belong to this genus. 



M. pijriila is a Membraniporinu species which bears a close resemblance to 

 Cribrilinu jigiilaris. I shall just mention thai the od'cia have also in this .species 

 a median suture, and that the eclooo'cium appears to have a large, uncalcified 

 region on eather side. It is however not so well delined as in Cr. /Kjiihiris. 



Aspidelectra n. g. 



Membranij)orella Hi neks. 



The proximal part of the zoircium with 1 — 2, thick, projecting, hollow spines; 

 the frontal shield perforated by slits; each distal wall with 2 multiporous rosette- 

 plates, and the distal half of each lateral wall with a single one; the aperture in 

 the frontal shield with an opercular valve; no ai'icuhiria; no o(vci(t. 



A. melolontha, the only species hitherto known, must certainly be traced to 

 Electra and appears to show specially close relationship to E. (tngiilata. with 

 which species it agrees not only in possessing 1 — 2 jjrojecting spines, but also in 

 having an angularly bent distal wall with a mulliporous rosetlc-[)late in each of 

 the two basal corners. 



Arachnopusia .luUien'-, char, emend. 



The frontal shield, which has a small number of large holes and avicularia 

 of varying size, is formed by the coalescence of a number of branched, originally 

 hollow, later partially solid spines, which spring from the lateral walls. A mem- 

 branous opercular valve. The angular distal wall has a number of uniporous 

 rosette-plates while the rosette-plates of the lateral walls have 1—3 pores. 

 Hyperstomial owcici with a wholly calcified ectoooeciuni and an ooecial cover 

 formed by the adjoining frontal shields. The distal wall is in the ooecia-bearing 

 zooecia continued frontally beyond the proximal part of the otrcium into a lamina 

 terminating in a rounded, sometimes crenulated margin, from which a membranous 

 ocecial operculum takes its origin. 



To this genus belongs Crihrilina inonoceros M. Gill, which however comprises 

 several rather different forms, that may possibly be considered independent s])e- 

 cies. Cr. lerniinnhi M. Gill. '' may probably also be referred to Ibis genus. It has 

 at anj' rate a prolongation ending in a crenulated margin similar to that found 



' 108, p. 5. - 45, p. 62. ' 76, p. 5U. 



