ALASKA NEMERTEANS 6 1 



TJENIOSOMA Stimpson. 



Tceniosoma Stimpson, Proc. Acad. Nat. Sci. Philadelphia, p. 162, 1857. 

 Polia Delle Chiaje, Mem. sulla storia e notomia degli anamali senza 



vertebre del regno di Napoli, Naples, 1823-28. 

 Eiipolia Hubrecht, Report of Challenge! Exped. Zool., xix, 1887. 

 Enpolia Burger, Fauna u. Flora von Neapel, Monogr. 22, p. 598, 1895. 



For the reasons given on page 4, it seems absolutely necessary to 

 adopt for this genus the name given by Stimpson in 1S57 ratner than 

 accept that of Hubrecht of 30 years later, even though most European 

 writers have ignored Stimpson's brief, but careful, diagnoses. 



The species belonging to this genus show a remarkable specific vari- 

 ation in the general shape and size of the body. Some are character- 

 ized by extremely long, slender, flattened, and much twisted bodies, 

 while others are short, thick, and cylindrical. In all the species, how- 

 ever, the head in life is rounded in front and is sharply marked off 

 from the parts immediately following by lateral constrictions. Hori- 

 zontal furrows are wanting, but small, oblique or transverse grooves 

 may be present on the head. In strong contraction the esophagal 

 region becomes greatly swollen, the head is drawn in (p1. ii, fig. 4), 

 so that the anterior end of the body is large and shortly truncated. 



Proboscis sheath and proboscis short, seldom reaching more than 

 one-third the length of body. Proboscis opening subterminal, minute. 

 Mouth a small round opening on the ventral surface immediately be- 

 hind the ganglia. 



Muscular layers of body composed of a thick outer longitudinal, a 

 circular, and a less thickened inner longitudinal layer. Outside the 

 muscular layers is a well developed cutis, composed of a thick inner 

 layer of connective tissue, and an outer layer of glandular tissue. The 

 external epithelium is thin, as compared with the other layers of the 

 body, though the fibrous layer separating it from the cutis is well de- 

 veloped. The musculature of the proboscis consists of an inner longi- 

 tudinal, and an outer circular muscular layer. Consequently there can 

 be no muscular crosses. 



The cephalic glands are enormously developed. They stretch back- 

 ward on all sides beyond the brain, and even reach some distance into 

 the esophagal region. 



The lateral nerves lie immediately outside the circular muscular 

 laver. There are three longitudinal blood vessels. 



Ocelli are usually present in great numbers, though very small. 



The worms are sluggish in their habits, are unable to swim, and 

 usually show great irregularities in the diameter of the body. They 



