24 



In the northern seas, we know a state of the true Cribrilina annulata r ), in which it 

 very nearly agrees with the constitution of the Cribrilina punctata. Thus, all these 

 species, in their developmental and calcificational changes, follow the same way, from 

 a more flustrine (with more plain frontside and greater pores of the zooecia) to their 

 most typical escharine state (with more convex frontside and smaller pores of this 

 side), and very often they will be confounded with each other. So far as they yet are 

 known, with their nearest allies, they will thus be arranged: 



1. Ooecia imperforata: 



A: Avicularia, ubi adsunt, inter zooecia disperguntur; Vibrissa? (vibracularia?), ubi 

 adsunt 2 ), ad marginem aperturse, lateri zooeciorum affixre sunt: 

 cc: Porus medianus deest: 



Cribrilina radiata, 

 ti: Area pone aperturam zooecii poro media-no lunato perforatur: 

 Cribrilina innominata. 

 B: Avicularia, ubi adsunt, ad marginem aperturae posita lateri zooeciorum affixa sunt: 

 a: Avicularia, ubi adsunt, apice proxiinaliter vergunt: 



«: Porus medianus deest; margo proximalis aperturae zooecii primarius 

 horizontalis manet: 

 acc Margo aperturam zooecii setosa: ■ 

 Cribrilina floridana, 

 ftfi: Margo aperturae zooecii setis caret: 

 Cribrilina figularis. 

 fi: Porus medianus aliquando adest; margo proximalis aperturae zooecii in 

 mucronis formam porrigitur: 



Cribrilina nitido-punctata. 

 b: Avicularia, ubi adsunt, apice distaliter vergunt: 



Cribrilina punctata. 



2. Ooecia poris perforata: 



«: Zooecia inarmata: 



Cribrilina annulata, 

 ft: Zooecia aviculariis munita: 



Cribrilina, puncturata. 



Escharipora (?) mucronata n. sp. (Pl. V, figs. 113 — 115). 



Char.: Zooecia ovalia, ad margines cancellata, aperturam semiellipticam vel longi- 

 orem, postremo quadrangularem prsebent, angulis rotundatis; frontem me- 

 diam prsebent por.is vulgo tribus reniformibus, in annulum positis, interne 

 denticulatis perforatam, mucrone ad aperturam erecto prseditam. Avicularia 



') Öfvers. Vet. Akad. Pörh., 1867, Bih., p. 54, pl. XXIV, fig. 10. 



2 ) When these bristles eau be demonstvated always to be raissing iu the European forms, then the Ploridan 

 varieties will take their own names. 



