173 



Gen. 41. Modiolicola, Aurivillius, 1883. 



Generic Characters. Anterior division of body moderately dilated and 

 more or less depressed, with the 1st trunk-segment well defined from the 

 cephalon. Tail slender and attenuated. Integuments thin and soft. Anterior 

 antennas 7-articulate and of a structure similar to that in the preceding genera. 

 Posterior antennae slender and almost naked, with the penultimate joint unusu- 

 ally prolonged; apical claws 3 in number. Maxillae with the terminal lappet 

 much produced, falciform; palp small, tri-setose. Anterior maxillipeds without 

 the usual lateral spine on the distal joint. Posterior maxillipeds in female 

 much reduced, in male well developed, prehensile. Natatory legs with both 

 rami 3-articulate in all the pairs; inner ramus of 4th pair with no setae inside 

 the terminal joint. Last pair of legs uniarticulate, bisetose. 



Remarks. This genus was established in the year 1883 by Aurivillius, 

 to include a peculiar Copepod found by him parasitic within the valves of the 

 well-known mussel Modiola vulgaris. The genus is chiefly distinguished 

 from those treated of in the preceding pages by the distinctly 3-articulate inner 

 ramus of the 4th pair of natatory legs, and partly also by the structure of the 

 posterior antennae. Otherwise this genus is rather closely allied to Lichomolgus. 

 In addition to the type species described below, Canu has recorded another 

 species under the name of M. inertnis. Only the type species has been 

 observed by me. 



93. Modiolicola insignis, Aurivillius. 



(PI. XCVII). 



Modiolicola insignis, Aurivillius, Bidrag til Kannedomen om Krustaceer, som lefva hos Mollusker 

 och Tunicater, p. 10 & 39, PI. II, figs. 110, PI. IV, figs. 18. 



Specific Characters. Female. Body moderately slender, with the 

 anterior division rather expanded, rounded oval in outline, and pronouncedly 

 flattened. Cephalic segment large and slightly produced in front, exhibiting 

 behind a very distinct transverse suture limiting the cephalon from the 1st 

 pedigerous segment. Epimeral plates of the 3 succeeding segments evenly 

 rounded off. Tail equalling in length 2 /s of the anterior division; genital seg- 

 ment about the length of the 3 succeeding segments combined, and some- 

 what tumid in its anterior part, which is rather sharply defined from the 

 cylindrical posterior part; anal segment a little smaller than the preceding one. 



23. Crustacea. 



