160 



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

 avicularia may appear. The frontal shield with pores. 



Cr. figularis, Cr. philomela v. armata and Cr. clithridiata ^ belong to this genus. 



M. pyrula is a Memhraniporina species which bears a close resemblance to 

 Cribrilina figularis. I shall just mention that the ooecia have also in this species 

 a median suture, and that the ectooojcium appears to have a large, uncalcified 

 region on eather side. It is however not so well defined as in Cr. figularis. 



Aspidelectra n. g. 

 Membraniporella Hincks. 



The proximal part of the zooecium 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 avicularia; no ooecia. 



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

 Electra and appears to show specially close relationship to E. angulata, with 

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

 having an angularly bent distal wall with a multiporous rosette-plate in each of 

 the two basal corners. 



Arachnopusia JuUien^ 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 ooecia with a wholly calcified ectoocecium and an ocecial cover 

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

 zocecia continued frontally beyond the proximal part of the ocecium into a lamina 

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

 ocecial operculum takes its origin. 



To this genus belongs Cribrilina monoceros M. Gill, which however comprises 

 several rather different forms, that may possibly be considered independent spe- 

 cies. Cr. terminata M. Gill. ^ may probably also be referred to this genus. It has 

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



'■ 108, p. 5. ^ 45, p. 62. ' 76, p. 59. 



