2:?3 



Scuticella sacculata l^usk. 

 Catenicella sacculata Busk, Challenger, Zoology, Vol. X, Part I, pag. 12, PI. 1, (ig. 7. 



(PI. XII, ng. 2 a). 



The zooecia, the surface ol' which is provided with a number of very small, 

 widely scattered pores, are long, slender and constantly increasing in breadth 

 Irom the very narrow proximal end towards the aperture, from which the lateral 

 margins again converge distally. The aperture has a slightly concave proximal 

 margin, and Ihe extremely small sternal area has ])ut a single, small, round 

 fenestra proximally. The sternal sinus is occuj)ied by three spines, of which the 

 proximal, rudimentary one is solid, while the two others, which meet in a sutural 

 line, have an inner cavity opening outwards through a small pore near the di.s- 

 lal margin. The sternal cryptocysl lamina has an arch-shaped proximal margin, 

 which is clearly visible on Ihe frontal surface through Ihe only opening of the 

 htller. 



The lateral chambers. The scapular chamber is everywhere except on the 

 adzoa^cial side of the daughter-zocrcium developed as a medium-sized, rather 

 strongly projecting and somewhat ascending avicularium, which is direcled out- 

 wards and slightly basally. The other chambers are wholly membranous and 

 bounded only by low calcareous ridges. The supra-scapular one, of which but 

 an extremely small part is seen on the basal surface, on the frontal surface 

 almost reaches the distal margin of the ajjcrture and Ihe outer end of Ihe roof 

 of the avicularium. The infra-scapular one, which is direcled laterally, is ralher 

 large and of an oblong, (juadrangular or pentagonal form. It is separated by a 

 small intermediate space from the very long and rather broad pedal chamber, 

 which is situated a little more frontally and occupies about two-thirds of the 

 whole length of the zoa-cium. Along its middle we lind a row of 6 — 7 rosette- 

 plates. The mother-zoa'cium is provided with a long, narrow, infra-scapular ad- 

 zon'cial chamber. 



Ooecia have hitherto not been found. 



This species may l)e regarded as a transitional lorui between Scuticelld and 

 Cdleiutriii. I have been able to examine a small fragment of il, for which I owe 

 IhanUs to the direction of the British Museum. 



Costiceila n. g. 



The sternal area, which is provided with 4 — 14 fenesfrse, disposed in a curved 

 line, and with a cryptocysl lamina of a similar outline, is to a greater or smaller 

 extent formed by a number of generally hollow spines, springing from the sternal 



