1881.] THE SURVEY OF H. M.S. 'alert.' 35 



Tectura (Pilidium) coppingeri, sp. 11. (Plate IV. figs. 12, 

 12a.) ' ^ ^ ' 



Shell cap-shaped, thill, sculptured with numerous fine, thread-like, 

 granulous lirse radiating from the apex to the margin, and with fine 

 concentric lines of growth. The colour is dirty white, varied with 

 two or three bands of a pale slate-colour which encircle the shell at 

 irregular intervals, and are interrupted by the radiating liree, which 

 are white. This feature is more apparentwithin the shell, where the 

 surface is very smooth and shining. Margin nearly simple, very 

 faintly crenulated by the extremities of the ridges, roundly ovate in 

 form. Apex rather acute, not greatly curved down, and very near 

 the anterior end. Length 5^ millims., diam. 4^, height 2|. 



Hub. Station 7. 



This is the southern representative of the northern Tectura 

 {Pilidium) fulva of Miiller. It is rather more circular than the latter ; 

 and the colour of the single specimen at hand is different. 



Chiton bowenii. King. 



Hab. Cockle Cove, 2-32 fathoms., mud bottom. 



Chiton (Callgchiton) illuminatus, Gray. 

 Hab. Station 6. 



Chiton (Plaxiphora) carmichaelis, Gray. 

 Hab. Stations 3 and 6. 



Chiton (Tonicia) fastigiatus, Gray, 

 Hab. Tom Bay, on the shore. 



Chiton (Ischnochiton) imitator, sp. n. (Plate IV. figs. 



Shell elongate ovate, moderately elevated, subangularly arched at 

 the middle, dirty white. Valves narrow, with a single notch on each 

 side, exhibiting small slightly raised lateral areas, which towards the 

 margin have a few transverse strong grooves or marks of growth. 

 Front margin sloping very slightly on each side from the middle in 

 a posterior direction ; hind margin straight. Sculpture consisting 

 of close flat granulation, exhibiting a somewhat serial arrangement. 

 Laminae of insertion very thin, with a wide sinus between them. 

 Anterior valve sculptured like the others, with fourteen fissures 

 ■within, the thirteen teeth between them being sharp and straight- 

 edged. Posterior valve with a central mucro, from which there is a 

 faint ridge on each side to the lateral extremity, also marked with 

 concentric lines of growth at intervals, and with the inner marginal 

 fissures twelve in number. Scales of the mantle minute, imbricating, 

 ovate, arranged lengthways ; under the microscope they appear 

 ^very coarsely transversely grooved. Length 11 millims., diam. of 

 fourth valve 5. 



Hab. Tom Bay, on the shore. 



This species is very like the northern C. albus ; and C. viridulus of 



3* 



