Crustacea. 251 



throughout its length laterally, and a few inconspicuous ones are 

 scattered dorsally ; two above the average size are situated dorsally 

 about the middle of its length. The extremity is rounded, and bears 

 two divergent and prominent terminal spines. 



First antenna, normal structure, reaches to about two-thirds the 

 length of the thii'd joint of the second antenna. Setae on terminal 

 joint few. 



Second antenna. The two basal joints each with stout spine, 

 the third joint with three stout spines, proximal shortest, distal 

 largest, fourth joint with two spines proximally situated, and the 

 fifth joint is slightly the longest. Flagellum missing. 



Thoracic appendages. The three pairs of setose limbs bear a 

 stout spine on the ischium and meros ; the basis has several of 

 varying length. The three posterior, which are essentially ambula- 

 tory in character, have a few blunt spines on the basal joints. The 

 meros, carpus, and propodos bear a few slender forwardly-curved 

 spines on the inner margin. 



The opercular shield of the pleon is covered with short spines. 

 A single specimen of this species was taken off Franklin Island 

 in 10-24 fathoms of water, and a temperature of 29 • 8° Fahr. It is a 

 female, and its body is largely concealed by a vigorous growth of 

 Spirorbis and other tubicolous worms, as well as diatoms of large size.^ 

 Exclusive of antennae, the animal measures some 15 mm. in length. 

 Three other specimens were taken at this locality ; they are of 

 smaller size, but I am not as yet disposed to make a new species for 

 them. With the exception of the two frontal spines, the two 

 terminal spines of the pleon, which are only stumps, and a few very 

 small spines on the lateral margin of the pleon, the bodies are quite 

 smooth ; they are, in spirit, light-coloured, and covered with minute 

 brown spots. The second antennae of two of the specimens is per- 

 fectly smooth, but in the third, and largest, there are obvious traces 

 of developing spines. This would indicate that these specimens are 

 not yet mature, and to give them a specific rank does not seem to 

 me to be desirable. 



ISTOTASELLUS AUSTRALIS. ^ 



(PI. XXXVI.) 



Specific character. Uropoda longer than pleon, which is 

 approximately as broad as long, and terminates in a rounded 

 projection. 



1 Mr. V. H. Blackmau informs me that the diatom belongs to the genus 

 Triceratium. 



