314 



c/ia/Zeng'erfa Waters' (= Myriozoum immersum Busk) and Orthopora compacf a Waters ^ 

 To the last author is due the demonstration of the peculiar ooecia in T. stellata 

 and S. challengeria. I have been able to examine small fragments of the first 

 three species, but my material has not been sufficient to settle the question, 

 whether they should be referred to one or to several genera. 



Family Eurystomellidae n. f. 



No spines. The thick-walled and strongly calcified zooecia lack a covering 

 membrane and have either no pores at all or 2—5 extremely large fenestrae. 

 The broad aperture, which has a concave proximal rim, is provided with a more 

 or less strongly chitinized operculum surrounded by a continuous marginal thick- 

 ening. No avicularia. The ocecium is enclosed in a kenozocecium, the frontal wall 

 of which is provided with a very large uncalcified part. Pore-chambers or groups 

 of uniporous rosette-plates. 



To this family I refer »Lepralia«^ foraminigera Hincks^ (PI. XVIII, figs. 14 a— 14 c) 

 and »Lepralia<' bilabiata Hincks*. and I regard them provisionally as belonging to 

 the same genus Eurgstomella. There may possibly be reason however to form a 

 special genus for L. bilabiata. In this species the distal wall and the distal half 

 of each lateral wall are provided with a group of numerous small, uniporous 

 rosette-plates, whereas multiporous pore^chambers occur in L. foraminigera. 



Family Escharellidae n. f. 



The zooecia, which are often armed with (2—8) spines, have as a rule a dis- 

 tinct vestibular arch, in many cases even strongly developed. If avicularia occur, 

 they are as a rule lateral and there is never a median, symmetrically placed 

 avicularium. Pore-chambers usually present, more rarely uni- or multiporous ro- 

 sette-plates. The ocecia which are as a rule hyperstomial, very seldom endoooecial 

 consist of a membranous, more rarely partially calcified ectoooecium and of a 

 calcified endoooecium, which usually shows no pores and more rarely has small 

 scattered pores. 



Whilst I have found a covering membrane in the genera Escharella, Escharo- 

 ides, Schizoporella, Escharina and Cyclicopora, 1 have been unable to find this in 

 Anarthropora, Exochella and Arthropoma, of which genera I have examined colonies 

 preserved in spirit. Though I am inclined to attach no little weight to this character, 

 I have for several reasons not ventured to make this negative result decisive as 

 to whether I should refer the genera mentioned to this family. In the first place. 



0, p. 30. ^ 115, p. 75, ' 28, p. 109. ■* 34, p. 49, 



