234 



sinus and separaled l)y fissures. Hinge-teelh riidinienlary or indislinci, ni'vcr pro- 

 jecting I'leely in the aperture. The supra-scapular chanil)er with a calcilied roof. 

 The occlusion takes place in a similar way to that in Sciiticella. 



Besides in the ahove nienlioned characters the four species heie described 

 correspond in the folioNving. The scapular chamber is generally developed as a 

 small avicuhniuni also on the adzod'cial side of Ihe daughter-zon'ciiiiu, and Ihe 

 first three lateral chambers form a more or less compressed, piolruding and 

 somewhat frontally directed, wholly or mostly calcified portion, which is separated 

 from the frontally directed pedal chamber by a rather large intermediate space. 

 There is a very small supra-scapular clKunber on the adzod'cial side of Ihe 

 mother-zott'cium and a [)edal chamber on Ihe adzooecial side ol" the daughler- 

 zoo'cium. The l)asal wall of the zoircia has a more or less distinct, longitudinal 

 strialion. The gonozo(ecia, situated either on a mother-zocx'cium or on an inserted 

 zooeciuni, are always provided with at least two frontally directed lateral cham- 

 bers, which must be regarded as the scapular and the pedal. The frontal surface 

 of the covering kenozott-cium has two large, transversely oval fenestras, and within 

 each of these we find on the ooeciuni a long, dense collection of spinous pro- 

 cesses and tubercles, among which numerous pores are generally discovered. 

 Further a larger or smaller part of the frontal surface of the true oa'cium is 

 provided with robust spinous processes, which have coalesced with the inner 

 surface of the kenozoa^cium. On the top of the latter we sometimes find a small 

 kenozoa'cium, sometimes a small avicularium communicating on either side with 

 a small calcified lateral chamber. 



Costicella solida n. sp. 



(1^1. XX, fi«. 7 a, l>\. XII, tigs. 1 k, 1 li). 



The sternal area, which is not much longer than the aperture, has 5 — 6 

 fenestrse situated in a broad curve, within which a ([uadrangularly rounded cryp- 

 tocyst lamina is seen. In the inner part of the area there are 5 — 7 very short 

 spines separated by distinct fissures, which show great variation in respect to 

 their mutual connection. The two distal ones are generally very high and plate- 

 shaped, and each of them has most fie(juently a larger or smaller, often bifur- 

 cate, inner cavity, which is connected with a pore in the middle of the oral 

 margin. In Ihe others Ihe inner cavity is usually wanting or if i)resent extremely 

 narrow. 



The lateral chambers. The supia-scapular chamber has a triangular excision 

 on its frontal surface near the ajierture and a smaller one in the outernu)st, 

 proximal part of Ihe basal surface, .while the infra-scapular and Ihe [)edal cliam- 



