64 A MONOGRAPH OF THE TERTIAllY POLYZOA OF VICTORIA. 



Family MiCROPORELLiDiE. 



Zo.-irimii ciierustini'' or erect and iini- or l)ilaniinat(\ Zoa^cia horizontal, 

 calcareous ami destitute" of membraneous area; froni with a single pore or 

 l)(M-forated \)\n\:c or with several pores opening into the perivisceral cavity; 

 thvrostome arcluvl ahove, entire below. Ocecia prominent and external, or modihed 



Y.OiVC'vA. 



Tlu' ess(>ntial character of this family is tlie prest^ice of one or more pores 

 opening directly into llie cavity oF the zooccium. Two groups, diifering in several 

 points, but agreeing in the cnrdinal one of tli(> zou'cial pore, are included. In the 

 one, containing of those here described, Microporolla and Tcssaradonia, the owcia 

 arc of the usual marsupial form, and external. The other, of which Adrona 

 (including Ad ront'll apsis) is the only genus, dill'ers chiefly in the ocecia not being 

 external and distinct, but being internal and consisting of modified zocecia {(jonoecia 

 of llincks.) It also dilVers in having, in addition to ordinary sessile avicularia, other 

 Inrger avicularia developed in s])ecial cells variously distributed among the zocecia. 

 These characters, however, although important and very interesting, can scarcely be 

 considered of sufficient value to distinguish a separate family. The genus Adco)iella 

 of Busk agre(>s with Adeona in having gonoecia and vicarious avicularia, but differs 

 in having the pore on the anterior surface, when present, formed by a process from 

 each side of the lower lips uniting to form an arch beneath, which it opens into the 

 peristomial chamber in front of the true thyrostome. In the only species w^hich I 

 have found fossil there is no pore, but other specimens may probably show it. I 

 have referred Adeonella to the Schizoporellida;, to which this species seems to 

 belong, as do also A. {Eschara) dispar (McG.) and A. phdidca (Busk), as well as 

 several others, at least of the Challenger species.* 



Microporella, Qrmj. 



Tiiyrostoine arched nhove, straight below ; a single circuhn- oi' lunate pore 

 {Irifjw of Gregory), or a perfoi*ated plate below the lower lip. Oa^cia external. 



1 . 31. cUUda, Linn, sp. i'l. IX., fig. 3. 



Lppndm cilia/a, Busk, B.M.C., Pt. If., 73; kl., Crag Bol., 42; McG., P.Z.V., 

 37; Microporrl/H nil i(i/<f, mncki^,BM.r., 2(H); Busk, C.P., Pt. I., 138 ; Waters, 

 Q.J.G.S., 1SS2, 1). 206 and 508; id., 1887, p. 53; McG., P.Z.V., 175. For other 

 references mikI synonyms, see B.M.P. and Miss Jelly's Catalogue. 



Zoarium encrusting. Zotecia distinct, ovate, graiuilar, several (usually foui") 

 oral spines; a small lunate or rounded pore [fri/jjo) below the thyrostome; a sessile 



•For a discussion of this subject see Hincks, A.M.N.H., Feb., 1887. 



