Page:Transactions NZ Institute Volume 15.djvu/96

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,^[1] the figure of which 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, Guérin-Ménev., and is found at Kerguelen's Island.^[2]

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. Pl. I., fig. 1.

Head moderately large, transverse, about twice as broad as long, produced obtusely between the bases of the antennæ. First thoracic leg short and stout, second long and slender, the rest more like the first though not quite 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 ⅙ of an inch.

Hab. Timaru, among seaweed at north side of the breakwater; Lyttelton Harbour.

Additional remarks on structure:—

The eyes are moderately large and placed wide apart at the posterolateral angles of the head.

The upper antenna (fig. 1a) 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 setæ” are found. These at first appear to be egg-cup shaped bodies, having a stout base from which arises all round a curved portion forming the cup. But careful focussing will show that there is