472 BALAJUD/E. 



The palpi are rather small, with long spines at their ends. The man- 

 dibles have four (sometimes five) teeth, with the inferior portion pecti- 

 nated. The maxillae are notched. 



Cirri. — The first pair presents no remarkable character. The second 

 and third pairs are subject to extreme variation, as in Chthamalus 

 antennatus and Tetraclita jwrosa. In all the specimens, the anterior 

 ramus of the second cirrus is short, with all the segments thickly 

 covered with bristles; it i* the posterior ramus which varies so much in 

 relative length and in the arrangement of the bristles; but in no case 

 are all the segments clothed with bristles as on the anterior ramus, 

 and as is normally the case with all sessile cirripedes. In some speci- 

 mens from New Zealand, the anterior ramus having only five segments, 

 the posterior ramus was twice as long, having sixteen segments, with 

 the bristles arranged in circles, but standing rather thicker together on 

 the basal segments. In a Tasmanian specimen, the posterior ramus 

 was only a little longer than the anterior ramus, and the spines were 

 arranged in regular pairs (as on the three posterior pairs of cirri) on all 

 the segments, excepting the few basal ones, on which they were more 

 crowded : a nearly similar arrangement occurred in some other speci- 

 mens from unknown localities, excepting that the rami were of nearly 

 equal length. In the third cirrus, in all the specimens, the anterior 

 ramus has three or four of its basal segments much broader than 

 the upper segments, and thickly clothed with spines (as is the case 

 with one species of Chthamalus, viz. C. intertextus) all the other 

 segments having regular pairs of spines. The posterior ramus of the 

 third cirrus varies in being either much longer than, or only equal in 

 length to, the anterior ramus; in the former case (in the New Zea- 

 land specimen) the spines were arranged in circles, giving an antenni- 

 formed structure to the ramus; and in the latter case they were 

 arranged in regular pairs. In Mr. Cuming's great Australian specimen, 

 there was a further peculiarity, in the presence on the posterior cirri of 

 a tuft of intermediate spines between the main pairs; and, in there being 

 on those segments, which are thickly covered with spines, certain very 

 large spines, doubly pectinated, with the pectinations elbowed, 

 closely like the spines met with on the cirri in certain species of Pol- 

 licipes. Finally, the segments in the three posterior pairs of cirri sup- 

 port five or six pairs of main spines ; the dorsal surfaces of the seg- 

 ment are rough and hairy. 



Branchice, rudimentary; consisting of a small, simple, tongue- 

 formed fold, projecting about T J th of an inch. Ova, -oo§o tns °f an 

 inch in length. 



2. CHAMiESIPHO SCUTELLIFORMIS. PL 1 9, fig. 4 tf 4 d. 



Rostrum very small, elongated, triangular : lateral com- 

 partments, each with an aperture, and carina with two 

 similar apertures, all four leading into shell g tubular 

 columns. 



