78 W. M. Bide: 



tliecae are uioi'e compressed latei'ally than tliose of 0. caliculata, 

 aijil in most of tliem the sides, in tlie broader aspect, are not con- 

 vergent, so that in this view the cavity appears as if perfectly 

 cylindrical, with a flat floor. A much thickened annular band, 

 convex in section, encircle.s the disttl half of tlie hydrotheca com- 

 pletely; fi'oni the lower edge of this band to the floor the wall is 

 less thickened. The hydrothecae freijuently have the compressed 

 condition extended in some degree to the distal portion, so that 

 tlie aperture may l)e elliptical. The bead-like segment immediately 

 l)eIo\v the hydrotlieca is noticeably narrower than the peduncle on 

 which it is s\ippoi-ted, a feature not observable in 0. calicidatn. 



The rounded summit of the gonotlieca f(jrms a convex cap, which 

 separates at maturity. There are usually tv,o gonozooids, which 

 ai'B described by Von Lendenfeld as medusoid buds, which do not 

 Ijccome free, and in fact do not possess a properly developed um- 

 Inella at the time when the sexual products a)e matui'ed. He adds 

 that they are similar to those of C . callcuJata . 



Orthopyxis avilsoni n. sp. (Pis. XI. and XIT., Fig. 5). 



Hydrorhiza rather slender, peduncles strongly waved, conunonly 

 2-4 times as long as the hydrothecae. 



Hydrothecae usually thin-walled, but occasionally slightly thick- 

 ened, thickening principally near the top; mostly somewhat bell- 

 shaped in the broad aspect, rather more funnel-shaped in the narrow 

 view, with the thickening absent or scarcely indicated ; border plain, 

 very slightly eveited : length, .34 — .43 nnii., width at aperture, 

 .25— .33 mm. 



Gonothecae very large, not compressed, sub-cylindrical, equal in 

 diameter thioughout except at the basal part, divided into about 

 seven or eight longitudinal areas by lines which run from the summit 

 to near the base; no operculum, irregular fornis frequent. Length 

 when mature, about 1.95 mm., diameter, .75 — .87 nan. Gono- 

 phores large, medusoid, umbrella with 8 otocysts (?). 



Ifah.—Vovt Phillip (Mr. J. Bracebridge Wilson). 



Many of the hydfothi'cae show no thickening, others appear in 

 tht' liroadcr aspect sliglitly thickened in the fashion of O. calicnlatn, 

 or with a, sub-marginal band in the same jxisition as that of 0. 

 iixicrofioiui l)ut much less pronounced. The two aspects differ but 

 litlle. the cavity l)eing somewhat more broadly rounded at the base 

 in one view than in tlie other. The ])eduncles usually have the 



