On a New Species of Littoral Oligochseta 

 (Pontodrilus matsushimensis). 



By AKIRA IIZUKA, 



Zoological Institute, Science Coll., Imp. Univ., Tokyo. 

 With Plate II. 



During a shorb excursion to Matsusbima Bay, Province of Rikuzen, 

 lasb August I collected, among other annelids, an oligochaßte referable to 

 tbe genus Pontodrilus, of which only five species* have been recorded 

 from other parts of the world, but as yet none from our coasts. As the 

 species in question presents some remarkable points of difference from 

 any of the known members of the genus, I think it worth while to 

 publish its description. 



It is found burrowing in sand, under the half decayed leaves of 

 Zostera marina, along the shores of Matsusbima Bay, from low tide 

 mark to a certain distance farther up, beyond, as it seems to me, high 

 tide mark. There is no indication of its presence on the surface of the 

 sand, so that it can only be obtained by indiscriminate digging. I my- 

 self bave obtained only a few specimens, but Mr. B. Onodera of Shiwo- 

 gama, a small town on the western side of the bay, has been able to send 

 me a large number of them living in kind compliance with my request. 



Most of the specimens before me are sexually mature. 



* (1) Pontodrilus littoralis, Grabe from tbe shores of the Mediterranean, (2) P. 

 bermudensis, Beddard from Brazil, Bermudi), and Jamaica. (3) P. hetperidum, Beddard 

 from Jamaica. (4) P. insulari*:, Rosa from the Aru Islands. (3) P. phosphorexts Dugès 

 from North France. 



