358 LITHOTRYA CAUTA. 



made its habitation in one of the valves of so small a shell 

 as a Conia. Shell white, exterior membrane, where pre- 

 served, yellow, and bearing small spines. Thoracic seg- 

 ments, the lower segments of the second, third, and fourth 

 cirri, all the segments of the first cirrus and the trophi, 

 slightly mottled with darkish purple. 



Mouth. — The teeth or beads on the crest of the labrum 

 are blunt, few, not very small, and equidistant. 



Palpi, bluntly pointed. 



Mandibles, with the three main teeth nearly equal in 

 size ; the pectinations are equal in number, namely, only 

 three between the first and second, and the second and 

 third main teeth • the inferior angle is coarsely pectinated, 

 with one central spine much longer than the others ; the 

 distance between the tips of the first and second main 

 teeth, equals that between the second tooth and the in- 

 ferior angle. 



Maxillce, with the tw T o upper spines very large ; beneath 

 them there are two small spines, and a considerable notch ; 

 the inferior part of the edge is nearly straight, bearing 

 about thirteen pairs of spines, obscurely divided into two 

 groups, the lower spines being smaller than the upper 

 ones. The upper convex margin is hirsute with long hairs. 



Outer Maxillce, blunt, with the inner margin slightly 

 concave ; continuously, but thinly clothed with spines. 



Cirri, — The segments of the three posterior pairs bear 

 four pairs of spines, with the usual intermediate fine spines; 

 dorsal spines thin and thick mingled together. First 

 cirrus, short, with the anterior ramus rather the thickest 

 and shortest \ all the segments thickly paved with bristles, 

 except the two terminal segments, of which the ultimate 

 one bears some serrated spines of most unusual length, 

 namely, equalling within one segment the entire length 

 of the ramus. I presume that these spines serve as feelers. 

 Second cirrus; anterior ramus much thicker and con- 

 siderably shorter than the posterior ramus; six basal 

 segments paved with bristles, the two terminal segments 

 having the usual structure; posterior ramus with all its nine 



