REPORT ON THE ISOPODA. 47 



I am unable to give any details respecting the two following pairs of appendages save 

 that they are thin plates evidently serving as gills. 



The uropoda resemble in almost every particular those of Ischnosoma bacillus, they 

 are shown in fig. 13 of PI. VI. 



Station 302, south-west of Valparaiso, December 28, 1875 ; lat. 42° 43' S., long. 

 82° 11' W.; 1450 fathoms; bottom temperature, 35°"6 F.; Globigerina ooze. 



Acanthomunna, F. E. Beddard. 



Acanthomunna, F. E. Beddard, Proc. Zool. Soc. Lond., 1886, pt. i. p. 102. 



Definition. — Body everywhere densely beset with short slender spines, many of which 

 are branched. Head short and comparatively narrow, furnished with eyes elevated on 

 stalks like those of Munna ; the general outline of the thorax is oval, the body being 

 widest at the third thoracic segment. The abdominal shield is oval and very convex 

 anteriorly, posteriorly more flattened, and terminating in a truncated and crescentic 

 posterior margin. Antennules with four basal joints of which the third is the longest, 

 and a long multiarticulate flagellum. Mandibles furnished with a palp. First pair of 

 thoracic appendages sub-cheliform, the remaining thoracic appendages are long and 

 slender, the posterior pairs longer than the anterior ; the limbs terminate in a single 

 elongated claw, and are spiny. Uropoda defective, articulated to the (apparently) dorsal 

 surface of the caudal shield. 



Remarks. — Two specimens of a deep-sea Isopod, belonging apparently to the same 

 species, are referred to this genus; they were dredged in 700 and 1100 fathoms respec- 

 tively off New Zealand. The genus is remarkable for its dense sj)iny covering, a condition 

 met with in other deep-sea and cold-water Isopoda ; it agrees with Munna in the general 

 form of the body, in the elongated thoracic appendages, and especially in the stalked 

 eyes ; the structure of the antennules, however, and the presence of only a single 

 elongated claw upon the thoracic appendages are distinctive marks of difference from 

 that genus. In all probability the structure of the uropoda is different ; the appendages 

 themselves were unfortunately defective in both specimens, but the large socket upon the 

 dorsal surface of the abdominal shield, which is evidently the point of articulation, seems 

 to me to indicate that these appendages were far less rudimentary than those of Munna, 

 and they must in any case be larger. 



Acanthomunna proteus, F. E. Beddard (PI. XII. figs. 7-14). 



Acanthomunna proteus, F. E. Beddard, Proe. Zool. Soc. Lond., 1886, pt. i. p. 103. 



The present species is the only representative of the genus. There are two specimens 

 among the Isopoda collected by the Challenger, one from off New Zealand at a depth 



y 



