Male o/Dexamine tlieu, Boech. 121 



Remarks on the Male of D. thea. 



The body is much more slender than in the female and 

 also somewhat more compressed. The eyes are compara- 

 tively very slightly larger, the pigment being very dark 

 brown with a lighter coating. Both pairs of antennte are 

 comparatively more slender and elongated. Antenna 1, 

 flagellum 14-1 6- jointed. Antenna 2, ultimate joint of 

 peduncle subequal to penultimate^ flagellum slightly longer 

 than peduncle and 11-12-jointed. The pro[)odos of the first 

 pair of gnathopoda * is peculiarly modified, having on the 

 upper margin a somewhat deep sinus. Although somewhat 

 resembling the propodos of the first pair of gnathopods of 

 the male of Tritata gihhosa (Bate), yet it appears to differ 

 in one or two points. The notch in the hand of the last- 

 named S2)ecies appears to be deeper, and the upper margin 

 is not so much rounded as in D. thea, while the disposition 

 of the setse is somewhat different, and these setic are also 

 more numerous than in the just-named species. The 3rd to 

 5th peraeopods are of similar construction to those we find in 

 the female^ although they are not so setous, while the 

 uropoda are not so spinous as in the opposite sex. The 

 telson is cleft nearly to the base, each half with three lateral 

 spines, one subdorsal and one on each finely serrated apex. 



Colour yellowish, semipellucid, mottled with pink and 

 orange. 



Length 2'5 to 3*5 mm. 



The reason why the male had not been previously known 

 is probably due to the facts : 1st, that the male is always 

 apparently of smaller size than the female, and thus might 

 be passed by as younger specimens ; and 2ud, because the 

 first gnathopod, when not in use, seems to be habitually 

 tucked away among the mouth-organs and is not visible 

 without dissection. 



It may be interesting to state that I have taken T. gihhosa 

 from the outer integument of Ascidia mentula, O. F. M., 



* IJoLertsou (14) lias drawn attention to the occurrence of tliis notch 

 ill the/t »/«/«' of TrH(cia (jihhuMi (Bate). lie ."states: "Moreover it ha^ 

 been observed in female specimens, so tliat probably the unnotched form 

 of the hand belonjrs to individuals not adults, unless the species //iiit)*vi 

 and dolkht'mjx are distinct." Stebbing- (17) observes, "occasionally also 

 in $ , perhaps a copulatorv feature." In my invesligations among the 

 Clyde Crustacea during the past tAvelve years, I have come across two 

 female specimens of this species where the propodos of the first gnatho- 

 pods had a slight notch only (I'l. V. iig. yn. 1. $ ), but the hnnd was of 

 the normal structure otherwise, and unlike that of the male. 1 have Uut 

 come across this pcculiaritv iu tlie female o( Uf.vatiiiiic thea. 



