BRYOZOA 47 



There is one interesting thing, shown in one of the sections, for before fossilisation the 

 two layers hâve been slightly separated, and the various zoœcial chambers hâve been somewhat 

 displaced. The individual zoœcia of the fossil now readily separate. 



Habitat. — Exp. Antarct. Belge. 



N° 991, Tangles VIII. Lat. 70 00' S.- Long. 8o° 48' W. ; 5oo ?met.; -I- 0.9 C. 



Fossil : Patagonia (Aquitanian or Burdigalian). 



Lepralia frigida sp. nov. 



(PI. III, fiffS. g<7. b, & PI. VIII, fig. 9) 



Zoarium adnate. Zoœcia ovate or in older growth irregularly hexagonal, surface 

 porcellanous and granular. In ail but the younger zoœcia, there is near the aperture but 

 rather below it, a stout process, which has on the inner side a semicircular avicularium, 

 though from the position it is not always possible to see the opcning and mandible. The 

 aperture is much depressed, so that the shape of the opercular aperture can only be distinguished 

 when it is possible to look down the peristome ; the operculum has the distal end rounded, 

 the sides nearly straight and the proximal edge subtriangular ; there is a thickened ridge 

 curved at each side and the muscular attachment is verv high up, being close to the distal 

 end. The ovicell is small, short, distinct, not much raised, very finely granular, with the 

 zoœcial wall in some cases covering the sides. 



A pièce decalcified, in order to prépare out the opercula shows, that the zoœcial 

 chambers are connected together through long tubes (PI. VIII, fig. g) one to each neigh- 

 bouring zoœcium, with a communication plate near the one end ; and as there are some 

 other species connected by long tubes, this structure will hâve to be taken into considération 

 in classification. The zoœcial chamber as seen from below is nearly round, but as seen 

 from above it expands to the opercular end. 



This is an interesting species in showing resemblances to Lepralia and to Schizoporella 

 as well as in having the muscular attachment of the operculum so near to the distal end. 

 The thickened ridges of the operculum suggest Lepralia, but in not having a straight proximal 

 edge it is like Schizoporella. In the group known as Schizoporella the opercular attachment is, 

 in species when there is a wide sinus, placed higher than in other cases ; as examples of the 

 wide sinus are S. biaperta Mich., S. marsupifera Busk, S. laevigata Waters, S. tnmida Hincks, 

 whereas where there is distinct sinus as in S. Cecilii Aud., S. arcinata H., S. vulgaris Moll, 

 S. armata Hincks, S. cribrillifera Hincks (') the muscular attachments are placed lower down. 



Neviani has given the naine Hippoporina to the Lepralia of Hincks, because the genus 

 Lepralia had formerly included forms now belonging to various gênera, and perhaps Hincks 

 would hâve clone better to hâve given the genus a new name, instead of retaining the 

 name for a subdivision, after the genus had been entirely subdivided. However the Lepralia 

 of Hincks has been generally adopted, and while it may ultimately be advisable to accept 



(1) S. cribrillifera Hincks and perhaps 5. armata H., as well as S. magninca H. may fall into Phonicosia of 

 Jullien, but the genus made from one spécimen and based on one character cannot be accepted until further 

 vvork has been given to the group. 



