234 



DISCOVERY REPORTS 



Of this species two young stages were found. The first (Fig. 3, a) is a pupa without 

 any traces of the valves. The prehensile antennae are typical for Scalpellum. 



The second stage (Fig. 3,Z>) shows an individual with all the capitular valves 

 and the first four scales of the peduncle formed. The upper latus was originally 

 quadrangular. The lower latera have not reached the development of the mature stage. 

 They are all rather low triangular plates. The prehensile antennae are not lost in this 

 stage. 



Female. Capitulum with fourteen plates, all well calcified and separated by very small 

 chitinous interspaces. The cuticle in the fully grown specimens is very thin and without 

 hairs. The middle part of the animal, especially the upper part of the peduncle, is 

 swollen, as is the case in many old individuals of Scalpellum. All plates with very distinct 

 growth ridges and longitudinal striations. Thus the species is beautifully striated. 



Fig. 3. Scalpellum liberum. a. Pupa without valves (total length 0-75 mm.), b. Young specimen 

 which has not lost prehensile antennae (total length 1-30 mm.), c. Holotype, lateral view (total length 

 II mm.), d. Carina and carinal latera. e. Holotype, rostral view. 



Scutum quadrangular, with the occludent margin straight and the apex projecting 

 freely. The lateral margin comparatively short. 



Tergum triangular, with recurved apex. All margins bowed. 



Carina simply curved, with an apical umbo. Lateral parts developed in the upper 

 part of the plate. The dorsal roof convex in the middle, with very indistinctly indicated 

 lateral ribs. The same shape of carina is to be found in typical S. velutinum, Pilsbry, 

 1907. 



Upper latus in fully grown specimens triangular, with umbo apical and distinctly 

 projecting. The scutal margin a little concave. 



Rostrum well developed in comparison with the rostrum in S. velutinum, Pilsbry, 

 1907, and triangular in shape with the umbo at the apex. The valve is much like the 

 scales of the peduncle, and not overlapped by the rostral latera. 



Rostral latus triangular and nearly as high as wide. 



