LEPTOECIA. 319 



Entangled in the setae of one of the specimens were a number of vegetable 

 fibres and cells. These were chiefly stellate idioblasts of large size, probably 

 from some decayed terrestrial plant. This is not at all surprising in view of 

 the fact that Mr. Agassiz found terrestrial debris so abundant at all depths in 

 this region. In his letter concerning the explorations of the Albatross in this 

 region he says: "Nearly everywhere except on the face of the Galapagos slope 

 we trawled upon a bottom either muddy or composed of Globigcrina ooze, more 

 or less contaminated with terrestrial deposits, and frequently covered with a 

 great amount of decayed vegetable matter. We scarcely made a single haul 

 of the trawl which did not bring up a considerable amount of decayed vegetable 

 matter, and frequently logs, branches, twigs, seeds, leaves, fruits, much as during 

 our first cruise." (Bull. M. C. Z., 1891, 21, p. 190-191.) 



Leptoecia, gen. nov.^ 



Prostomium with two short, thick, frontal tentacles and five posterior, or 

 dorsal, tentacles each provided with a ringed ceratophore. A pair of cushion- 

 like palpi separated ventrally by a median fissure. 



Peristomium simple and very long, bearing no tentacular cirri. 



Body flattened, especially posteriorly; not obviously narrowed cephalad, 

 but at the caudal end narrowed acutely. Anus terminal on pygidium. Anal 

 cirri apparently two. 



First parapodia large, extending directly forwards along the sides of the 

 peristomium but not attaining the prostomium. Ending distally in a flattened 

 process and bearing unjointed hooded crochets. 



Ventral cirri soon becoming reduced to pads. Dorsal cirri decreasing in 

 size caudad and disappearing in the posterior region. 



On the anterior parapodia, excepting the first, occur limbate and delicate 

 pectinate setae, while farther caudad there occur strong hooded crochets and 

 other limbate setae. 



Maxillae of the usual number and arrangement, with all parts well developed. 

 Mandibles also well developed, with long shafts and rather narrow, subfoUate, 

 masticatory plates. 



Branchiae none. 



Tube thin, translucent, without foreign material. 



Genotype. — L. abyssorum, sp nov. 



' XtTTTos thin, and oiKia, house. 



