212 B ALAN ID j:. 



thin, with their delicate denticuli not extending to the outer lamina : 

 they are very porose. The alee have their summits parallel to the basis; 

 their sutural edges are most finely cremated. The sheath is blueish, 

 excepting the wedge-like portions of the alse which have been added 

 during the diametric growth, and these are white. 



Mouth: labrum without teeth: mandibles with five sharp teeth: 

 maxillse with the edge straight. Cirri, first pair with the rami very 

 slightly unequal ; segments of the shorter ramus and of both rami of 

 the second pair protuberant : posterior cirri with the segments shield - 

 shaped in front, bearing four pairs of spines, of which the upper pair 

 is much longer than the lower pairs ; each pair has a small intermediate 

 tuft of minute spines. 



G. Balanus decorus. PL 2, fig. 6 a, 6 b. 



Parietes pale pink; radii rather darker. Scutum with a 

 small articular ridge. Tergum with the longitudinal 

 furrow very shalloio and open ; basal margin on both sides 

 sloping toicards the spur. 



Hab. — New Zealand. Mus. Brit., and .Flower : attached to shells. 



General Appearance. — Shell conical or tubular, with a large rhom- 

 boidal orifice; very pale pink, but tinted yellowish from the persistent 

 epidermis, and sometimes faintly striped longitudinally; radii and 

 sheath of rather a darker pink ; scuta in themselves white, though 

 lined by purple corium ; the carinal half of the tergum pink. Walls 

 extremely smooth. Largest specimen above one inch in basal dia- 

 meter. 



Scuta, with the finest striae radiating from the apex ; growth-ridges 

 moderately prominent ; articular ridge small ; there is a very slight 

 and blunt adductor ridge : the hollow for the lateral depressor muscle 

 is rather narrow and deep. 



Terga, with the apex slightly prominent or beaked ; the longitudinal 

 furrow is of very little depth ; on its scutal margin there is a narrow, 

 rounded, slightly prominent ridge, which, however, appears more like 

 a furrow than a ridge. Spur moderately long and blunt ; placed at 

 half its own width from the basi-scutal angle ; the basal margin on 

 both sides of the spur, slopes gently towards it. Internally, the 

 articular ridge is pretty well developed ; the scutal margin is not much 

 inflected ; the caiinal portion of the under surface of the valve is rough ; 

 the crests for the carinal depressor muscle are entirely absent. 



Compartments. — Walls moderately strong: parietal tubes small, with 

 transverse septa in their upper ends ; inner surface of the walls much 

 less strongly ribbed than is usual. Radii broad, with their summits 

 parallel to the basis ; their septa are strongly denticulated. Alee 



