118 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.53. 



To the ends of each band and all over the dorsal surface of the 

 ring numerous muscle bands are attached, which have their origin 

 on the dorsal and posterior walls of the head. Similar muscle bands 

 are inserted all over the ventral wall of the head around the mouth, 

 on the soft membranes as well as on the harder chitin parts. These 

 also have their origin on the dorsal, lateral, and posterior walls of 

 the head, so that the entire cavity, except for the digestive tube, is 

 filled with these muscle bands. 



Their contraction pulls in the ring and the portions of the ventral 

 wall around the mouth as far as the elasticity of the chitin and the 

 soft membranes will permit. The entire front of the head thus takes 

 the place of the protrusible proboscis in other genera. 



The esophagus, after passing through the ring, turns forward 

 and opens on the ventral surface of the head in the space between 

 the anterior bands (oe). There is a posterior prolongation (p) 

 which extends backward between the ring and the ventral wall of the 

 head, and ends blindly between the posterior bands. Behind this 

 prolongation posteriorly and along either side of the ring are irregu- 

 larly rounded areas (m) in the ventral wall of the head, which are 

 covered with a fairly thin, soft membrane instead of the hard chitin. 

 Between these areas and outside of them the walls are thick and 

 hard; the frontal processes cover both the hard chitin and the soft 

 membranes indiscriminately, and can be removed from the latter as 

 well as the former without injury. The number, size, and arrange- 

 ment of these soft membranes furnish good specific characters. 



Color (preserved material), head and anterior fifth of the thorax 

 dark yellowish brown; remainder of thorax and trunk light yellow 

 on the dorsal and ventral surfaces and dark brown along the sides; 

 plumose appendages silver gray ; egg strings light yellow. 



Total length, 235 mm. Head, 4 mm. long, 5 mm. wide. Lateral 

 horns, 35 mm. long. Genital segment, 50 mm. long, 4 mm. wide. 

 Abdomen, 18 mm. long. Egg strings, 100 mm. long. 



(antarctica, the region from which the original specimens came.) 



Remarks. — One of the specimens was an exceptionally fine one, and 

 the above description has been given in order to supplement the one 

 presented by Quidor and to correct certain errors. 



Quidor found but a single pair of antennae and he designated as 

 first maxillae two chitin knobs, one on either side, in the sinus of 

 the frontal margin, and thus in front of the mouth, between it and 

 the antennae; two others on the ventral surface were designated as 

 second maxillae, and only three pairs of legs were found. 



The species may be recognized by the exceptionally long and 

 slender neck and by the three horns on the first thorax segment, the 

 two lateral ones being long and inclined forward. 



