70 Transactions. — Zoology. 



Pleon with last segment large and triangular, emarginate at apex. 

 Last pair of pleopoda single-branched, consisting of a single broad squami- 

 form plate. 



This genus I have made for an Isopod of which I took several specimens 

 at Timaru, and since then at Lyttelton Harbour. It will, I think, come 

 nearest to Cassidina, Milne-Edwards ; however, it does not resemble C. typa 

 so much as it does C. latistylis, Dana,* the figure of wbich I have been able 

 to see through the kindness of Professor J. von Haast. According to Mr. 

 Miers, C. latistylis is the same as C. emarginata, Guerin-Menev., and is 

 found at Kerguelen's Island.! 



From Cassidina, however, my genus differs in having the last pair of 

 pleopoda unibranched. In Cassidina the outer branch is present, but is 

 almost rudimentary, while the inner and basal one is large and broad ; so 

 that Cassidina appears to be truly intermediate between Scutuloidea and 

 some genus such as Zuzara, which has the two branches equally developed. 

 Scutuloidea maculata, sp. nov. PI. I., fig. 1. 



Head moderately large, transverse, about twice as broad as long, pro- 

 duced obtusely between the bases of the antennae. First thoracic leg short 

 and stout, second long and slender, the rest more like the first though not 

 qixite so stout, all having the propodos ending in two strongly curved claws. 

 Segments of pereion subequal in length. Pleon of two segments, last large, 

 triangular, with a wide shallow notch at apex. Last pair of pleopoda each 

 consisting of a single broad squamiform plate, more than twice as long as 

 broad, narrowing posteriorly, the inner edge conterminous with the side of 

 the last segment of the pleon, and reaching very nearly to the end of pleon. 



Colour — pale yellowish-brown, whole body thickly covered with small 

 purple spots. 



Length about -J of an inch. 



Hab. Timaru, among seaweed at north side of the breakwater ; Lyt- 

 telton Harbour. 



Additional remarks on structure : — 



The eyes are moderately large and placed wide apart at the postero- 

 lateral angles of the head. 



The upper antenna (fig. la) is considerably shorter than the lower ; 

 the three joints of the peduncle decrease in size distally and pass insensibly 

 into the flagellum, which consists of but few joints. On the distal portion 

 of it "sensory setae" are found. These at first appear to be egg-cup 

 shaped bodies, having a stout base from which arises aU round a curved 

 portion forming the cup. But careful focussing will show that there is 



* U.S. Exploring Expedition, 1852, XIV., Crustacea, part II., 784; pi. 52, fig. 12. 

 t Trans. Eoyal Society, vol. 168 (extra volume), p. 204. 



