3 
where it appears as a voracious destroyer (observations in the latter 
case made in Japan). These examples from my own experience are, 
however, by no means confined to the aforementioned manner of 
occurrence; they live also among seaweed, under stones, etc. 
V. Graff in his paper on „Die Turbellarien als Parasiten und 
Wirte“ (Graz, 1903) has brought together the information at hånd 
concerning Polyclads found on other animals. Of the enumerated 
numbers 39 - 47, concerning Polyclads (1. c., pp. 38 - 40), the fol- 
lowing species are undoubtedly identifiable Polyclads (the names in 
parenthesis are used by v. Graff): Siylochus zebra (Verrill), in 
shells inhabited by Hermit Grabs; Hoploplana („Planocera'-) in- 
quilina (Wheeler) in the mollusc Sycotypus canaliculaius Giil; Hop¬ 
loplana („Planocera'^) insignis (Lang), one specimen collected in the 
branchial cavity of Murex brandaris L. (but another specimen found 
free living); Prosiheceraeus Giesbrechti Lang, the only specimen in 
Ciona intestinalis (L), and Cycloporus papillosus Lang („Planaria 
schlosseri Girard“) on Botryllus schlosseri var. adonis Girard (cfr. 
Francotte 1898). „Planaria'' velellae Lesson is possibly, according 
to V. Graff (1892 pag. 11) identical with Planocera pellucida 
(Mertens), found while consuming the soft parts of Velella. 
The remaining „Typhlolepta acuta Girard“, which in large num¬ 
bers crawl on Chiridota laevis, „Typhlocolax acuminatus Stimpson„ 
„in freto Behringi, parasiticus in Chiridotae specie" and „Crypto- 
coelum opacum Stimpson" „in echinarachnio magno" cannot be 
placed even as to the family, and it is, after all, very doubtful 
whether they are Polyclads. The first mentioned is later on spoken of 
by Verrill, who supposes it to be an Acoel or Rhabdocoel. v. Graff 
fails to mention, probably on purpose, Planocera simrothi v. Graff 
1892. The only specimen found in Janthina (in an empty shell?). 
Crozier describes in 1917 a Pseudoceros sp. „found in asso¬ 
ciation with various tunicates, upon the surface of which it has 
been seen to feed". Three colour „varieties", each on a different 
ascidian; the pigmentation due to the food. 
From Panama Dr. Mortensen has brought numerous speci- 
mens of an Emprosthopharynx and a few specimens of Euphrosthio- 
stomum adherens n. g. n. sp., both found in shells of the Pagurid 
Petrochirus californiensis Boucrez in two different localities. In 
Japan I found on a sea-urchin, Clypeaster, a new species of Neo- 
1 * 
