168 " THETIS " SCIENTIFIC RESULTS. 



which extends from the obtuse rostral tooth to the small lateral 

 denticles, opposite the inner bases of the outer antennae. 



Eye stalks with several tufts of hairs on their upper surfaces; 

 the subapical and basal tufts are much larger than the inter- 

 mediate ones. 



The basal joint of the second antenna has a small spine at its^ 

 outer distal angle; the acicle is compressed at the base and bordered 

 on each side by three or four spinules; the superior surface and 

 the outer margin bear some tufted hairs ; the inferior surface is 

 smooth, glabrous, and concave near the base. 



The third joint of the external maxillipedes is armed on its 

 inner acute margin with eighteen black denticles, subequal in 

 size and in distance apart. 



Meral joints of the first three pairs of legs spinose on their 

 lower borders. Upper borders of the second and third with a 

 few spinules disposed in short transverse rows and mixed with 

 long hairs. The first has the upper distal surface and the margin 

 strongly spinose. The succeeding joints are more or less covered 

 on their upper and external surfaces with spines having a 

 calcareous base and a corneous apex; as the distal extremities are 

 approached the corneous portion becomes more conspicuous and 

 forms more than half of the spine. 



The inner surface of the hand and mobile finger has some of 

 the spines elongated, appressed throughout, and disposed side by 

 side longitudinally, forming seven or more transverse rows. 

 These modified spines constitute a series of corrugations, which 

 when rubbed together produce a sound like that made by passing 

 the point of a penknife across the teeth of a comb. 



It is possible that these peculiar processes may be used for 

 other purposes than that of producing sound; they may possibly 

 be used for holding objects between the hands or to prevent the 

 latter from being forcibly moved either up or down when attacked 

 by an enemy. The slightest pressure brings the two corrugated 

 surfaces together, and they interlock so neatly that it requires 

 considerable force to raise or depress the claws. 



Mr. Waite informs me that when turned out on deck the 

 Hermit Crabs, both Pagttrus striatus and Clihcmarius strigimmi'ns, 

 would extend their bodies and limbs far out of their shells and 

 walk about. If, however, the shell or a limb was touched, or 

 even if a hand was passed within range of their vision, they would 

 instantly withdraw with a snap, their limbs rattling like old 

 bones ; for the space of a few seconds they then produced a loud 

 stridulating sound ; when recovered from their alarm they would 

 recommence their peregrinations. 



