120 



other 2 Neapolitan species, D fringilla and D. passer, it is at once distinguished 

 by the different form of the cephalic segment and the absence of any frontal crest. 



Occurrence. I have met with this characteristic form in many places of 

 the Norwegian coast, from the Christiania Fjord up to Finmark (Hammerfest). 

 All the specimens have been taken free in the sea among algse and other marine 

 growths, and there is indeed little probability that this form ever, as supposed 

 by Thorell, has its abode within the branchial cavity of Ascidise. 



Distribution. Christineberg (Thorell), British Isles (Brady), coast of 

 France (Canu), Bay of Naples (Giesbrecht). 



Gen. 29. CryptOpOHtiUS, Giesbr., 1899. 



Generic Characters. Anterior division of body less expanded and less 

 depressed than in Dyspontius, with the epimeral lappets more densely crowded 

 and curved backwards; those of penultimate segment very small, almost wholly 

 concealed. Tail short, but with unusually long apical setae. Structure of the 2 

 pairs of antennae about as in Dyspontius. Oral cone with the basal part con- 

 spicuously thickened and terminating in a very slender siphonal tube. Maxillae 

 with the lobes rather unequal in length and very narrow; apical setae on both 

 lobes slender. Anterior maxillipeds with the dactylus exceedingly slender and 

 elongated. Posterior maxillipeds normal. Natatory legs with the rami compara- 

 tively less slender than in Dyspontius; outer ramus of 1st pair without any seta 

 inside the 1st joint, terminal joint well developed, with 3 spines outside and 3 

 setae inside. 4th pair of legs without any inner ramus. Last pair of legs 

 exhibiting a rudimentary structure similar to that in Dyspontius. 



Remarks. The above generic diagnosis chiefly refers to the species 

 described below, as I am by no means certain that the other 3 species 

 referred by Giesbrecht to this genus are in reality congeneric. The chief dif- 

 ferences from Dyspontius are found in the general form of the body, the struc- 

 ture of the siphon, and the armature of the outer ramus of the 1st pair of legs. 



67. Cryptopontius brevifurcatus, Giesbr. 



(PL LXXI). 

 Cryptopontius brevifurcatus, Giesbrecht, Asterocheridse, p. 109, PI. 1, fig. 7, PI. 8, figs. 1 12. 



Specific Characters. Female. Body less expanded than in most other 

 Dyspontiidce, with the anterior division oblong oval in outline, greatest width 



