Description of Some Japanese Polyclad Turbellaria. 41 



Structurally the specimens present a close resemblance to 

 Oycloporw papillosum (!\I. Saus), a species widely distributed in 

 Europe.« 



The Misaki form seems to be closely allied to C. papillosus 

 var. l&vigatus, but may be distinguished from this in the appearance 

 of marginal tentacles. However, such a slight difference does not 

 appear to us to be of more than varietal value. 



Family Prosthiostoniirta» Lang. 



Genus JProsthiostonium Quateefages 1845. 



2 k 2. Prosfltiostomutn sipJutnculus (Delle Chiaje). 



(PI. II., fig. 13). 



Planaria siphunculnj, Delxe Chiaje 1828, p. 118. — 1841, p. 131. — Y<>i-any 1846, p. 9. 



Prosthioxtomum elongatum, Quatrefagks 1845, p. 136. — Stimpson 1857, p. 4. 



Schmidtlein 1880, p. 172. 

 Prostliiostomum aratum, Quatrefagks 1845, pp. 135, 136. — Stimpson 1857, p. 4. 

 Leploplava arcta, Diesing 1850, p. 196. — 1862, p. 538. 

 Lcptophma elongata, Diesing 1850, p. 196. — 1862, p. 538. 

 Prosthiostomvm hamatum, 0. Schmidt 1861, pp. 11, 12. 

 Leptqplana hamata, Diesing 1862, pp. 538, 589. 

 *? Prosthiostomnm emarginatvm, Lefckaut 1863, p. 169. 

 Mesodiscus inversiporus, Minot 1877, p. 451. 

 Prosthiostmmivi idphunciilus, Lang 1884, pp. 595-601. 



A large number of specimens referable to this species, original- 

 ly described from the Bay of Naples, were collected between the 

 tide-marks at Misaki, Matsuwa and Shirahama. 



Body elongate, for the most part nearly uniformly broad, 

 rounded anteriorly and somewhat pointed posteriorly. An average- 

 sized specimen in the creeping state measured 21 mm. long by 

 3 mm. broad. 



General colour of body buoy, growing deeper in tone towards 

 the median parts, nearly cinnamon over the main gut: pharynx 

 showing itself in a grayish colour but with a cinnamon median 

 stripe over the parts. Minute whitish spots scattered in the 

 median parts in a fairly numerous number. 



Cerebral eye-spots arranged in two, nearly linear groups; 

 marginal eye-spots arranged in a crescentic group along the frontal 

 margin, there existing commonly two spots in the width of it. 



