new and rare Crustacea J rum Scutlunt/. 11") 



Ilah. Vicinity of the Bass Rock, Firth of Forth. Hitherto 

 only one >i»ccinien, a t'eniale, has been obtained. 



h'emurk.s. The proportionally large and tumid cepiialo- 

 thorux gives this species a curious and striking appearance, 

 that at once distinguished it from any of the other Oopepoda 

 observed by us. It possesses all the characters of a Derma- 

 tomyzon, except that the anterior antennae are apparently 

 otily seventeen-jointed ; the second joint, however, is pro- 

 bably composed of three coalesced joints, so that the dif- 

 ference in this respect is trifling. It differs also in the 

 abdomen being composed of only three instead of four seg- 

 ments, and so far it agrees more closely with Asterocheres^ 

 Boeck, than with Dermatomyzon, Claus. Tlie Forth specimen 

 would thus appear to form an intermediate link between 

 these two genera, but with a closer affinity to the last. 



Acontiophorus elongatus^ sp. n. (PI. IX. figs. 15-20.) 



Length 1 millim. (v;'- of an inch). Cephalothorax aud 

 abdomen elongate ; tiie abdomen slender and equal to about 

 two thirds the length of the cephalothorax. Anterior 

 antennte slender, seventeen-jointed ; the fourth, fifth, sixth, 

 and eighth joints are shorter, and the first and last longer 

 than any of the other joints ; the formula shows their pro- 

 portional lengths — 



24 ■ 12 . 14 . 6 . 6 . 6 ■ 9 . 6 . 8 . 14 . 12 . 13 . 13 . 14 . 14 . 14 . 24 



1 2 3 4 5 G 7 8 9 10 11 12 13 14 15 16 17* 



The posterior antennaj are three-jointed, and a very small 

 secondary branch springs from near the end of the elongate 

 basal joint ; end joint small, and furnished with a long, 

 slightly curved, and slender terminal spine and a small mar- 

 ginal seta. Mandibles extremely long and slender, being 

 about equal in length to the elongate siphon ; the siphon, 

 which reaches to near the end of the cephalothorax, consists 

 of two slender filaments of equal length, one of which has 

 a ring-like structure and is armed with a small aj)ical stylet; 

 the basal part of the si])hon is stout and cone-shaped, and 

 encloses for some distance the proximal ends of the filaments 

 (fig. 18). Maxillee two-branched — one branch stout and 

 conical in shape, and furnished with one short and two long 

 setse ; the other branch narrow, not half the length of the 

 first, and bearing three setaj of unequal length. Anterior 

 and posterior foot-jaws somewhat like those of Acontiophorus 

 scutatuSj Brady and Kobertson ; but the last two joints of 

 the posterior foot-jaws are proportionally much longer than 



