284 



ascopore is silunled proximally lo Ihc cenlre of the Ixxly in a more or less devel- 

 o])C{i depression. The jiriniary a])erliire, which has no dislincl hinge-teelh, is 

 ahnosl semi-eircular and honnded l)y a proximal, nearly slraij<hl or slighlly eon- 

 vex margin. The operculnni (fig. 1 1) is not sejjaraled I'rom Ihe covering mem- 

 brane, and with the exception of a narrow marginal i)ortion it is meml)ranoiis; 

 only in old zoo-cia the part corresi)onding to the secondary aperUire may be 

 slightly chitinized. The secondary apertnre is of a somewhat variable, ronndish 

 form, most often somewhat broader than high, and with less concave, sometimes 

 almost straight proximal margin. Each zoa'cinm has in its distal half 14 — 10 

 uniporous rosette-plates and in its proximal half as many o[)enings. hi most corners 

 between tlie zoa>cia we find very small rounded cavities covered by a membrane, 

 which seem lo be kenozocecia. 



Avicularia. A long, narrow, pointed avicularium is fonnd in most zo(i>cia a 

 little distally to the median pore. It is directed towards (he aperture and may 

 reach some way past the proximal margin of the latter, histead of the avicularium 

 we find in a smaller number of zoa'cia (fig. 1 b) an annular ()i)ening, which 

 leads into an elongated, sometimes .somewhat swollen cavity. 



The gonozooecia, which are scattered singly or in groujis among the zocrcia, 

 are considerably larger than the latter and of an angularly oval form, ^hireover 

 they differ from the ordinary zon-cia by having a greater number of pores, a 

 broader, transversely oval aperture and two coalesced ascopores. The aviculariimi 

 is never developed, but is replaced by a cavity similar to Ihal found in a smaller 

 numlier of zoa'cia. 



Of this species I have examined a numl)er of colonics from Syracuse (rockj' 

 and shelly bottom, 12— 25 fm., Dr. H. J. Hansen), which occur partly incrusting 

 on calcareous alga;, partly in free, one-layered expansions. They agree with a 

 small colony from Guernsey (Norman) also in the possession of a single ascojiore 

 and of the small round kenozoo'cia, and as the latter thus contrary lo the de- 

 scriptions of Hincks and. lul lien, are not necessarily dcpcndenl on the |)resence 

 of a double pore, I find no reason for regarding Hincks's var. a as an inde- 

 pendent species, as Jul lien does. 



Adeonella serrata n. sp. 

 (I'l. XIV, lijis. 2a-2j.). 

 The zooecia, the finely tuberculated surface of which is covered by a light- 

 brown nu'mbrane, are generally rhomboidally vase-shaped, strongly arched and 

 provided with scattered i)orcs. Tlie primary aperluie, which is provided vvilli 

 well-developed hinge-teeth, has a large, well-defiiu'd, broadly rounded sinus imd 



