CHAPTER XX 



POUCHETIIDAE {continued) : PROTERYTHROPSIS, ERYTHROPSIS 



SUMMARY 



PROTERYTHROPSIS gen. nov. 

 Text figure PP, 9 



DiAOxosis. — Pouehetiidae with median girdle, posterior ocellus, stout rudi- 

 mentary tentacle or prodlike antapical process, witli no paracingular lines and 

 no recess about the base of the prod. Tj-pe species Protcrijthropsis crassicau- 

 data sp. nov. 



Discussiox 



This genus includes only a single species whose structure is such that it 

 is excluded on the one hand from Pouehetia and on the other hand from 

 Erylhropsis. It is a typical Pouehetia in all features except in the presence 

 of the posterior prod. The presence of longitudinal rows of pigment granules 

 is also somewhat unique for Pouehetia, within which the linear organization 

 of the peripheral plasma in any fashion is rarely evident, appearing as striae 

 only in P. striata, P. maxima, and P. violescens and as pigment granules with 

 the merest trace of linear aiTangement in P. maeulata. In the one species 

 known in P rot erijthro pais there is a well defined but locally restricted expression 

 of this linear organization in the arrangement of the peripheral spherules of 

 pigment. 



It is excluded from Pouehetia, however, by the presence of a posterior prod 

 not imlike those of Erijth ropsis, except in size, slight development, and absence 

 of a recess about its base. It is excluded from Erijtlirnpsis, however, not only 

 by this lack but also by the arrangement of girdle and sulcus, which is quite 

 t}Toical of that in Pouehetia, and also by the entire absence of anything sug- 

 gestive of the paracingular lines which parallel the girdle. In view then of the 

 absence of the recess, flattened epicone with apical horn, and paracingular lines, 

 it is impossible to include the species in Erythropsis. In view of the fact that 

 it affords a transition in structure looking towards the genus Erythropsis from 

 the types evolved in Pouehetia, the new genus Proterythropsis has been estab- 

 lished to receive it. The nature of its most characteristic structure, the postero- 

 ventral ]irod, is unfortunately not well established or fully described owing to 

 the mobility of the organ and of the organism carrying it. In so far as position, 

 direction, morphological relations, and activities are concerned, it appears to be 

 the same organ as the prod of Erythropsis, only in an initial stage of evolution. 



[474] 



