54. Ascomyzon parvum, (Giesbrecht). 



(PL LVII). 



Asterocheres parvus, uicslirecht. Fauna uml Flora cles Golfes von Neapel; 25th Monographie, Die 



Asterocheriden, p. 100, PI. 2, F. 



Specific Characters. Female. Anterior division of body less expanded 

 than in A. latum. the greatest width not nearly attaining the length. Cephalic 

 segment of moderate size and evenly rounded in front. Lateral parts of the 

 trunk-segments rounded off at the end, the antepenultimate segment not differing 

 in this respect from the others. Tail almost attaining half the length of the 

 anterior division, and having the posterior edge of the segments perfectly smooth ; 

 genital segment less broad at the base than in A. latin)} : anal segment about 

 the length of the preceding one. Caudal rami resembling in structure those in 

 the said species. Anterior antenna not fully as long as the cephalic segment 

 and composed of 20 articulations. Posterior antennae moderately strong with the 

 penultimate joint about equal in length to the preceding joint. Oral cone shorter 

 than in A. latum, only extending midway between the insertions of the posterior 

 maxillipeds and those of 1st pair of legs. Mandibles, maxillae, maxillipeds and 

 natatory legs differing very little in structure from those parts in A. lattnn. 

 Last pair of legs likewise very similar, though having on the distal joint a small 

 bristle inside the 2 apical setae. Ovisacs of moderate size, oblong oval in form, 

 and somewhat divergent, 



Colour light greenish. 



Length of adult female scarcely attaining 0.70 mm. 



Remark*. This species is closely allied to A. latum, but is of smaller size, 

 and moreover easily distinguishable by the less expanded anterior division of the 

 body, and the evenly rounded lateral parts of the trunk-segments. Finally, the 

 oral cone is considerably shorter than in A. latum. 



Occurrence. I collected this form, many years ago, in the upper 

 part of the Christiania Fjord, and. on account of its peculiar colour, noted 

 it with the provisional name .4. virescens. I have also found it occasionally off 

 the south coast, at Grimstad and Lillesand. All the specimens were taken in 

 the free state among dredged material. 



Distribution. Gulf of Naples (Giesbrecht), coast of France (Canu). 



