1470 THE VOYAGE OF H.M.S. CHALLENGER. 



is longer and broader than the outer, and broader than any of the other rami ; in this 

 pair each ramus has a cilium or setule at the rounded apex. None of the rami are here 

 long and acute as represented by Clans and Spence Bate for the young of the species 

 which they describe. 



Telson almost circular, reaching a little beyond the peduncles of the third uropods. 



Length. — About a fifteenth of an inch. 



Platyscelus serratulus, n. n. 



1879. Ewtyphis serratus, Claus, Die Gattungen und Arteu der Platysceliden, p. 11. 

 1887. „ „ Claus, Die Platysceliden, p. 37, Taf. iii. tigs. 5-14. 



The rostral angle produced, the segments imbricated. 



Lower Antennas, of the male, with the second joint of the flagellum rather longer 

 than the first. 



Epistome, as in the other species, forming a shallow dome, much broader than deep. 



Maxillipeds. — The outer plates very broad, the inner plate having two little 

 embedded spinules below the centre of the distal margin. 



First and Second Perasopods. — Third joint not very elongate, not much longer than 

 the fourth, the gland-cells not conspicuous ; fourth joint not much longer than the fifth. 



Third Perasojiods. — The third joint slightly longer than the fourth. 



Fourth Perasopods. — The first joint has a much longer slit on the outer surface than 

 is found in Platyscelus armatus or Platyscelus rissoinas. 



Localities.— April 28, 1876; North Atlantic; lat. 17° 47' N., long. 28° 28' W.; 

 surface, night ; surface temperature, 73°. One specimen. 



Station 348, April 9, 1876 ; North Atlantic ; lat. 3° 10' N, long. 14° 51' W.; surface 

 to 200 fathoms ; surface temperature, 84°. Four specimens, the largest, a male, under 

 one-fifth of an inch long ; in this specimen the fifth perasopods have a minute tubercular 

 second joint, and no third joint ; as in the specimen last mentioned the telson is distally 

 more narrowed than in Claus' figure. 



Station 106, August 25, 1873 ; between St. Vincent and St. Paul's Rocks ; lat. 1° 47' 

 N., long. 24° 26' W.; surface to 40 fathoms ; surface temperature, 78° - 8. One specimen, 

 female, a fifth of an inch long. In the fifth perseopods there are two small terminal 

 joints, the end one longer and thinner than the penultimate. 



Station 108, August 27, 1S73 ; off St. Paul's Rocks; lat. 1° 10' N., long. 28° 23' 

 W.; surface; surface temperature, 78°. One specimen. 



Remarks. — Claus, who identifies Platyscelus serratus, Spence Bate, with Typhis 

 ovoides, Risso, himself establishes a new species with the name Eutyphis serratus; as 

 the generic name Platyscelus is here allowed its right of priority, an alteration is at the 



