REPORT ON THE AMPHIPODA. 1587 



Oxyeephctius porceWas, Claus (PL CCIIL). Specimen A. 



1879. Oxycepkalw porcellus, Claus, Die Gattungeu und Arten tier Platysceliden, p. 48. 



1887. ,, „ Bovallius, Systematical List of Amph. Hyper., Biliang till K. 



Svensk. Vetensk.-Akad. Handl., Bd. 11, No. 16, p. 36. 

 1887. „ ,, Claus, Die Platysceliden, p. 72, Taf. xxiv. figs. 7-9. 



Head rather longer than the perseon, thick at the base ; the rostrum much 

 less acute when seen from above than appears from a lateral view, shorter than the 

 ocular region, the edges smooth ; the first three segments of the pleon with the postero- 

 lateral angles acute, a little produced ; the fourth pleon-segment dorsally as long as the 

 following composite segment measured to the base of the third uropods ; the composite 

 segment ventrally produced to the rami of the third uropods. 



Eyes occupying the sides of the head to the base of the rostrum. 



Upper Antenna*. — Peduncle short, the first joint not longer than broad, the second 

 incompletely developed ; first joint of flagellum long, curved, with a broad brush of 

 filaments, the upper margin slightly concave, with the apex rather strongly but not 

 extravagantly produced upwards ; the small second joint a little longer and broader 

 than the third, each with a small apical group of filaments ; the fourth joint linear, 

 a little longer than either of the preceding, tipped with setules. 



Lower Antenna?. — Third (first free) joint of the peduncle very long, curved, distally 

 ddated ; fourth joint longer than the third ; fifth a little longer than the fourth ; first joint 

 of the flagellum slender, fully as long as the third joint of the peduncle ; terminal joint 

 minute; the three joints of the peduncle and the first of the flagellum all closely fringed 

 with short filaments, and the terminal joint tipped with them. 



The Epistome appears to be helmet-shaped, with an Upper Lip of great tenuity, 

 transversely oval, but a little excavate on the lower margin. 



Mandibles.— ^Trunk very short compared with the palp ; cutting edge with a produced 

 tooth at the top, the rest of its margin straight, finely denticulate, the left mandible 

 having a shallow secondary plate, with its edge nearly as long as that of the principal, 

 the right mandible having a minute tubercle to the rear of the cutting plate ; the first 

 joint of the palp between three and four times as long as the two following joints together; 

 the second joint a little longer than the third, the two together forming a hook, both much 

 narrower than the first joint. 



Maxillipeds small, the inner plate widening distally, with the usual embedded 

 spinules at the centre of the front margin, the outer plates broad, with their broad 

 apices almost meeting over the inner plate. 



First Gnathopods. — The side-plates with the lower front angle produced forwards, 

 almost acute, having a ridge on the under surface running to the apex. The first joint 

 a little widened below the neck ; the second joint scarcely so long as broad ; the third 

 distally widened, broader than long, with a subapical spine on the convex hind margin ; 



