542 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 112 



It differs in the armature of the antermular lamina, the shape of the 

 antennal scale, the upward inclination of the alar spines, the fewer 

 spinules arming the apex of the telson, and above all in the short 

 poorly developed tergal spines from the last abdominal somite (fig. 

 7,«,/). 



Lophogaster sp. A 



Figure 6 

 Lophogaster sp. ? W. M. Tattersall, 1951, p. 20, fig. Id. 



Occurrence: Albatross station 4891, Ose Saki Light, Eastern 

 Seas, 32°27' N., 128°34' W., 1 <?, 20 mm. 



Description: Tattersall (1951, p. 20) gave a brief description with 

 a figure of the antennal scale of a single male specimen of Lophogaster 

 captured by the Albatross off the south of Japan. The following- 

 supplementary description can now be given : 



Carapace with the three spines of the frontal plate equal in length, 

 lateral ones slightly incurved; posterolateral angles produced into 

 short acute spines (fig. 6c). 



Antennular lamina well developed; extending forward almost to the 

 level of the apex of the antennal scale; inner margin slightly convex, 

 armed with fine plumose setae and terminating in a very small tooth; 

 anterior margin rounded, extending noticeably beyond the level of 

 the tooth; margin finely crenate (fig. Q,a,b). 



Tergal spines of the last abdominal somite very long and acutely 

 pointed; about one-eighth of the telson in length (fig. 6d). 



Telson with lateral margins armed with four very small spines and 

 a pair of long slender subapical spines. The tips of both apical spines 

 are broken off, but from what is left it is evident that they must have 

 been very long. Apical plate short and broad, armed with eight 

 spinules of which the median pair are extremely minute; a fine plu- 

 mose seta arises on each side between the outermost spinule and the 

 next (figs. 6,d,e). 



Remarks: In the form of the frontal plate, the shape of the antennal 

 scale and the armature of the telson, this specimen resembles L. typicus 

 but can at once be distinguished from it by the absence of tubercles 

 and postorbital spines on the carapace, by the form of the anterior 

 margins of the antennular laminae, by the well developed alar spines, 

 and by the very long acute spines of the last abdominal somite. 



It differs from the other Pacific species, pacificus, intermedins, and 

 hawaiensis, in the shortness of the rostrum, in the rounded crenate 

 anterior margin of the antennular lamina, in the small alar spines, 

 in the long acute tergal spines; in the larger number of spines arming 

 the lateral margins of the telson, and in the form and arrangement 

 of the apical spinules (fig. 6e). 



