82 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



also comparatively stout but are only about half the 

 length of the long seta. Anterior foot-jaws simple, bearing 

 a strong curved apical claw. Posterior foot-jaws elongate 

 slender, four-jointed, resembling those of Derma tomyzon 

 nigripes (B. and 11.). Both branches of the first four 

 pairs of swimming feet short and stout, three-jointed and 

 nearly equal in length. Fifth pair of feet rudimentary, 

 two-jointed, inner joint short and broad, furnished with 

 one plumose seta on its upper distal angle, outer joint 

 elongate, length about equal to twice the breadth and 

 bearing at its apex two moderately long plumose setae 

 and one small spine, both margins of the joint ciliated. 

 Abdomen three-jointed, genital segment about as long as 

 broad and nearly equal to the combined lengths of the 

 next two segments and caudal stylets, second joint about 

 half the length of the first, third joint about two-thirds 

 the length of the second. Caudal stylets slightly longer 

 than the last abdominal segment, length about equal to 

 twice the breadth. 



Habitat, 1 mile off Spanish Head, Isle of Man, in neritic 

 material dredged from a depth of 16 fathoms ; a few 

 specimens only were obtained. A number of specimens 

 have since been found in material washed from Ophiuroids 

 (Ophioglyplia and Ophiotlirix) taken in the trawl-net off 

 Blackpool, and sent to us by Mr. Ascroft. 



Bemarks. — This species is readily distinguished from 

 the other members of the Ascomyzontidce by the almost 

 oval outline of the cephalothorax and on dissection by 

 the structure of the mandible palp and maxillaB, the stout 

 setce on the larger lobe of the maxillae appears to be a 

 well marked character. Dr. W. Giesbrecht of the 

 Zoological Station Naples, is preparing a monograph on 

 this interesting family and an abstract which appeared in 

 the Ann. and Mag. of Natural History for August, ly ( J5, 



