ECHIUROID FAUNA OF NORTH PACIFIC — FISHER 481 



in several ways abnormal, a parallel development being found in 

 Ochetostoma arkati (Prashad). But these species agree with others 

 having a normal proboscis in the character of the nephrostome in 

 combination with the absence of longitudinal muscle bands. 

 The following species belong in this genus : 



a \ With 1 pair of nephridia opening behind setae abyssalis, new species 



^ With 2 pairs of nephridia opening behind setae. 



b \ Adherent proboscis with more or less frilly margin. 



branchiorhynchus (Annandale and Kemp) 



dendrorhynchus (Annandale and Kemp) 



marshalli (Prashad) 



& ^ Proboscis adherent but its margin not modified- microrhynchus (Prashad) 



sabinus (Lanchester) 



6 '. Proboscis deciduous semoni (Fischer) 



porcellus Fisher ' 

 a I With 3 pairs of nephridia. 



b\ All nephridia opening behind setae mucosus (Ikeda) 



vegi'andis (Lampert) 



6^ First pair of nephridia opening in front of setae inanensis (Ikeda) 



moebii (Greef) 



ANELASSORHYNCHUS ABYSSALIS, new species 



Plate 28 



Diagnosis. — Differing from all known species of the genus in hav- 

 ing only one pair of nephridia ; neurointestinal vessel connected with 

 dorsal vessel by numerous small vessels in wall of stomach ; therefore 

 no direct ring vessel present. 



Descjiption. — All specimens are in a deplorable condition, the vis- 

 cera having been lost through anus, probably owing to release of 

 water pressure. All have lost the proboscis and all except type the 

 setae and anterior visceral complex. None has the anal vesicles. 

 Longest specimen, probably unnaturally elongated, 230 mm.; type, 

 85 mm. ; slender, distorted. Body wall slightly translucent, probably 

 markedly so in life. Skin smooth, with numerous scattered papillae 

 ahnost flush with surface and more translucent than the skin, so that 

 they resemble tiny grains of cooked tapioca. In the head region 

 of type they are convex, opaque, and more normal, but not visible 

 without some magnification. Coelomic surface of body wall smooth, 

 but in contracted specimen the longitudinal layer is crossed by wavy 

 dark lines encircling body. 



Setae two, close together and close to mouth. They are 10 mm. 

 long with a relatively large, open, curved hook. The slender inter- 

 basal muscle is not surrounded by the neurointestinal vessel. The 

 very numerous basilateral muscles are long and slender. The muscles 

 from proximal end of sheath to lateral body wall are separated from 



1 Pacific Sci., vol. 2, p. 274, Oct. 1948. 



