236 LORICA. 



t. 54, f. 6, 6a. SMITH, Zool. Coll. H. M. S. ' Alert ' p. 82. HADDON, 

 Challenger Polyplac. p. 31. MOSELEY, Journ. Roy. Microscop. Soc. 

 xxv, p. 37, pi. iv, figs. 1-5 ; vi, f. 5 (eyes). Chiton elongatus REEVE, 

 Conch. Icon., f. 40. Schizochiton polyophtalmus ROCHEBRUNE, Bull. 

 Soc. Philomath, de Paris, 1881-'82, p. 191. 



This species is so unlike other forms that comparisons are 

 unnecessary. The eyes are larger than in any other form known 

 to me. A single eye is shown in fig. 3, magnified 200 diameters. 



The girdle is not well shown in fig. 1, the spines being too evenly 

 distributed over it. They are always closer at the sutures. 



Genus XVII. LORICA H. & A. Adams, 1852. 



Lorica H. & A. Ad., Annals and Magazine of Natural History, 

 (2) ix, p. 355 (April, 1852). Only species L. cimolia, Chiton cimo- 

 lius RVE. Aulacochiton SHUTTL., Bern. Mittheil. p. 68 (June, 1853), 

 type Chiton volvox REEVE. 



Valves exposed, not beaked, the lateral areas and end valves with 

 many fine riblets or pustules. Eyes confined to B single series 

 along the summit of each diagonal rib. Insertion-plates blunt, 

 obsoletely pectinated, the slits in head-valve not corresponding to 

 external ribs ; sinus very small. Posterior valve having the mucro 

 posterior and terminal, insertion-plate unslit, obsolete, being reduced 

 to a convex ridge of callus ; posteriorly cleft to the mucro by a deep 

 rounded sinus, or waved. Girdle slit or waved behind, densely 

 scaly. 



This is one of the few genera of " irregular " Chitons having a 

 scaly girdle. The eyes seem to be nearly obsolete, and possibly are 

 not functional, although they still are pigmented. In most spec- 

 imens a good hand-lens shows the series of ocular punctures along 

 the diagonal ridge, immediately in front of the anterior row of 

 pustules. 



The non-correspondence between slits and external ribs, the scaly 

 girdle, the transverse, unbeaked valves and the toothless posterior 

 insertion-plate, are all characters widely sundering this genus from 

 Schizochiton. 



Section Lorica s. sir. 



Sinus in tail valve deep; jugal sinus v-shaped; girdle widest at 

 the sides, cleft behind. 



