degree, of the arrangement of eyes. In the pharyngeal apparatus 
the difference is pronounced. In respect to the location of genital 
pores, we have, as already mentioned, an excellent agreement with 
Stylochus; it is further evident that it is less with Cryptophallus 
than with Par asty lochus. The female apparatus demonstrates closest 
resemblance to Parastylochus and Stylochus. The existence of a 
readily overlooked string of cells, interpreted as a rudiment of a 
ductus vaginalis, indicates perhaps that the resemblance is of a 
somewhat problematic nature, and that too great weight cannot be 
attached to it. As I have earlier pointed out, great caution must 
be used in regarding the female apparatus as a due to relation- 
ships. 
From this little exposé it follows that Ilyplana is a Stylochid 
of less pronounced characters. Of the Stylochids hitherto described, 
Parastylochus and Cryptophallus can be regarded as having perhaps 
the nearest relationship to it. In respect to habitus and pharyngeal 
apparatus these two genera appear, however, as typical Stylochids. 
But, they are approaching the condition met with in Ilyplana, in their 
tentacles being insignificant. 
The genus Ilyplana receives the following diagnosis: 
Stylochids with a delicate body of elongated oval outline. Mar¬ 
ginal eyes all around the body. Cerebral eyes in two clusters, 
and tentacular eyes few. Rudimentary tentacles. Pharynx of 
moderate size, approaches the brain. Intestine only branching and 
the coeca not densely gathered. Genital pores close to each other 
and near the posterior end of body. Small horizontal prostatic 
vesicle with undivided lumen. Penis large, fleshy, without penis- 
sheath. Cyanophile giands empty their secretion into the antrum 
masculinum. No seminal vesicle. Vagina short, without Langs 
glandular vesicle. 
One species from New Zealand. 
Leptostylochus elongatus n. g. n. sp. 
(Plate III, Figs. 11 — 16). 
Locality: Underneath stones on the shore of Ponui Island, Auck- 
land, New Zealand. 
Material: Eight specimens preserved in formalin. 
