146 TWAJI IKEDA. 



or without papi]la3, which a're but poorly developed ; the 

 genital opening lies in a narrow longitudinal groove of the 

 skin (the genital groove), in which also lie crowded numerous 

 ventral hooks wanting the muscular sheath and radial 

 muscles ; the anal glands are more than two in number and 

 branch off sever;d times before ending in funnels ; the oviduct 

 is one and unpaired, with a stalked funnel. 



Male. — The body is long and slender, the whole surface 

 being uniformly ciliated. N^o ventral hook is present; the 

 spermatic duct is long and wide, with a single funnel opening 

 to the body-cavity. 



The two species are briefly described as follows : 



ACANTHOHAMINGIA SHIPLEI, n. S.p. 



A deep-sea Hamingia-like fJchiuroid. The proboscis 

 is long and narrow, and ends Avith a rather abruptly pointed 

 tip. The skin is thin and partly semi-transparent, and' is 

 covered with small papillas poorly developed. In the middle 

 part of the genital groove are rooted and crowded the small 

 and numerous hooks with a curved and pointed apex. The 

 neuro-intestinal vessel is disproportionately long ; the dorsal 

 and neuro-intestinal vessels arise from the gut at two widely 

 separated places. The anal glands consist of four main 

 stems on cue side. The single oviduct and the parasitic 

 males are of the same form and structure as those of 

 Ac. ijimai. 



ACANTHOHAMINGIA IJIMAI, IkEDA. 



Synonym: Hamingia ijimai, Ikeda. 



A deep-sea Echiuroid having nearly the same external 

 feature as iliat of the preceding species. The proboscis ends 

 with a rounded margin. The skin is thin, semi-transparent, 

 and devoid of any sort of papillae. The ventral hooks, which 

 are crowded in the middle of the genital groove, are less 

 curved and larger than in Ac. shiplei. The anal glands 



