Crossophorus collaris, Ilemprich & Ehrenberg. 345 



Crossophorus * collaris, Hemprich & Ehrenberg, 1828. 

 Syn. Ascaris ferox, Schneider, 1866. 



The general dimensions of the worm are : — length, male, 

 up to 65 mm., female 55 to 90 mm. Maximum thickness 

 1*3 mm. in the male, about 2 mm. in the largest female. 



The head measures 0'14-0*5 mm. across at the widest part 

 of the lips. The latter (tig. 1, D.> V.) are large, semicircular 

 in general outline, vvitli an indentation in the anterior margin, 

 and with projecting posterior angles. The dorsal lip (tig. 1, D.) 

 has two fairly conspicuous bilaterally symmetrical papillae 

 (tig. 1, P.). Each ventro-lateral lip has also two papillae, 

 but these are arranged asymmetrically with regard to each 



Fig. 2. 



Crossophorus collaris. Diagrammatic representation of the arrangement 

 of the row of fimbrise (dotted line) as it would be seen in a front 

 view of the head. 



other, as is indicated in Schneider's figure (1866, pl.ii. fig. 2),. 

 i. e., one papilla is situated a little to the ventral side of the 

 middle of the outer surface of the lip, while the other occupies 

 a more forward position at the tip of the more dorsal of the 

 two anterior horns of the " pulp." The latter papilla is very 

 small. 



There is a very distinct constriction behind the lips, occupied 

 by a " collar " consisting of an apparently double row of 



* Not Crossophorus, Brady, 1880 [Crustacean], Voy. H.M.S. < Chal- 

 lenger,' Zoology, i. 3, Ostracoda. 



