208 FUNAFUTI ATOLL. 



specimen in the collection the gill area has a total length of 

 3-3 cm. It is thus relatively much longer than in P. minuta 

 and P. sarniensis, and is also of a different shape. In these forms 

 the gill area, when viewed from above, presents, as Spengel 

 describes it, the appearance of an elongated narrow triangle with 

 its apex pointing posteriorly. In P. hedleyi, however, the gill 

 area, viewed from above, appears long and band-like, and is not 

 pointed at its posterior end. The gill pores open on each side 

 into a narrow longitudinal groove, which runs parallel with the 

 deep median groove, marking the position of the dorsal nerve 

 cord. The narrow bands of epidermis lying, one on each side, 

 between the median groove and the branchial grooves, and 

 hardly '5 mm, in width, are divided up by transverse lines into a 

 definite and fairly regular series of oblong or squarish areas, 

 characteristic for the species. The openings of the gill cavities 

 into the branchial grooves can only be made out in sections. 



Laterally to the branchial grooves, the epidermis is irregularly, 

 but very markedly annulated, the annulations being interrupted 

 below by the median ventral groove marking the course of the 

 ventral nerve cord. This ventral groove is much shallower than 

 the dorsal. In the branchial region the trunk is almost quite 

 cylindrical, measuring in greatest breadth 4.75 mm. It is not 

 possible, in this region, to speak of genital cushions, such as 

 Spengel* describes and figures for P. minuta (taf. 2, fig. 10), and 

 P. sarniensis (taf. 6, fig. 7). Indeed, sections through the 

 branchial region of P. hedleyi more closely resemble in general 

 form the section, figured by Spengel, through the branchial region 

 of Glandiceps talaboti (fig. 13, taf. 19), than similar sections of 

 P. minuta and P. sarniensis. 



Behind the branchial region proper there is a short exclusively 

 genital segment of the trunk, characterised by its greater trans- 

 verse breadth and the presence of distinct genital cushions, 

 similar to the much more extensive cushions described by Spengel 

 for P. miuuta and P. sarniensis. This region, in a fragment of 

 a large and apparently sexually mature individual, has a length 

 of 15 mm., with a transverse breadth of 6 mm. It not only 

 exceeds the branchial region in breadth but presents in sections 

 a very different outline ventro-laterally it is rounded, while 

 dorsally it is markedly concave on each side of the median ridge 

 formed by the dorsal nerve cord. The genital cushions are the 

 direct continuations of that portion of the epidermis forming the 

 lateral boundary of the branchial grooves. They form low and 

 thick lateral ridges, extending from the posterior end of the 

 branchial region up to within a short distance of the most 

 anterior liver sacs. 



*Loc. cit. 



