ARTOTEOGUS. 59 



Genus 2. ARTOTEOGUS, Boeck (1859). 



(Artotrogus, Asterocheres, Boeck, Tvende nye parasitiske Krebsdyr, 1859. 

 Ascomyzon, Thorell, Om Krustaceer i Asoidier, 1859.) 



Body broad, suborbicular or subpyriform ; cephalo- 

 thorax broadly ovate, composed of eleven somites, the 

 first of which is united with the head ; abdomen com- 

 posed of four segments, the first and second of which 

 are, in the female, coalescent. Anterior antenna com- 

 posed of nine, ten, or twenty joints, shorter than the 

 first body segment; posterior 4-jointed, bearing a 

 strong apical claw, unbranched or furnished with a 

 very small secondary branch. Mouth produced into a 

 siphon, which reaches near or beyond the hinder 

 margin of the first segment of the cephalothorax. 

 Mandible elongated, filiform, without a palp. Maxilla3 

 2-branched, setiferous at the apex. First and second 

 pairs of foot- jaws simple, bearing a strong apical claw, 

 first composed of two, second of four joints ; first four 

 pairs of feet having both branches 3 -jointed ; fifth pair 

 rudimentary, composed of one joint only. Animals 

 living in the branchial sacs of simple Ascidians or on 

 the integument of various marine Invertebrata. 



The three genera, Ascomyzon, Thorell, Asterocheres, 

 and Artotrogus, Boeck, appear to differ in no essential 

 character. The smaller number of antennal joints 

 found in Artotrogus cannot be looked upon as a cha- 

 racter of generic importance, yet this, together with 

 the more rounded outline, is really the only definable 



