37 



The course of ridges //, // is a concave one. Ridge / is at the same time one of the 

 limits of the hydroecial cavity B (textfig. 49). This cavity has very strong muscular walls; the 

 other ridges around this cavity are / /. These meet together in the point c' but this is not 

 clearly to be seen as the next facet, the most ventral one has two ridges which overlap this 

 point (PL \T, fig. 47). The length of the hydroecial cavity measured from point / to ridcre i 

 measures 8 mm. 



The combinationfacets D -f CII + CI (textfig. 48) are club-shaped. We suppose that 

 this complex of facets is the same as in Abyla Leuckarti. 



The ridges are feebly serrated at the top but this gradually increases; near the point / 

 there are very clearly marked teeth. 



This combinationfacet is largest on the level of the somatocyst (4 mm.) and then narrows 

 suddenly; the ridges continue on each side; they meet at the top; their whole length is 21V., mm. 

 They meet in the point d' . 



Nearly 9^, mm. from point / the combinationfacet D + CII + CI shows an identation, 

 which appears also on the other surrounding facets. It seems as if the Dip/iyid-Wke upper 

 part had been put on the Aiylid-like lower part of the nectophore (PI. VI, fig. 47 «) and 

 that they had not yet quite grown together. When we draw a line parallel to the side 

 ridges of the facet D + CII + CI and one in the same direction with the side ridges of 

 the facet E which we will describe later, these two lines meet each other at an ano-Ie 

 of about 20°. 



Facet E (textfig. 47) is quite easily recognizable. It is situated on the proximal side; 

 immediately underneath is the nectosac (PI. VI, fig. 47). The side ridges (/&, k) have a length 

 of 24 mm. (measured from d' to ridge g of facet A); the distance between point d' and the 

 curved part is 8Vj mm. The ridges k, k show a little serrating at the top and this o-ets more 

 marked near the base ; it resembles the dentition near point e . The greatest breadth of facet E 

 is near ridge g. There it measures 2^/3 mm. 



In Abyla Leuckarti Huxl. we found three odd facets and the opening of the hydroecium. 

 This same number we find back in Diphyabyla Hitbrechti. The paired facets are two in number- 

 they too can be compared to the same facets in Abyla Leuckarti. 



In the latter we spoke of the complex facets F + G + H (F' + G' + H') because rido-e 

 .y did not continue to meet ridge //. This happens in Diphyabyla. 



So here we get again the usual facet F (resp. F' textfig. 49) and the combination facet 

 G + H (resp. G' + H'). 



This combinationfacet G -f H (textfig. 50) consists of four ridges. From point e the 

 ridge r goes off which is the combination of / -^ ^ e oi Abyla Leuckarti Huxl. This ridge 

 continues straight upwards but before attaining the top (4V0 mm. below it) it is joined by rido-e 

 .f of the other side. Basally is the ridge / of the hydroecial cavity. 



Ridge .f begins 1V3 mm. before the angle where ridge // and line / meet. It consists of 

 the combination of ridges / and ;;/. It is a little serrated, hardly prominent and has a total 

 length of 23V, mm. (15V2 mm. from its base to the curved part) and has its course right over 

 the median part of the hydroecial cavity. (PI. \"I, fig. 47). 



