NO. 2283. NEW PACIFIC COAST CHITONS— DALL. 509 



The absolutely irregular distribution of the brown pustules if char- 

 acteristic of the species is quite remarkable. They are not polished. 



ISCHNOCHITON EUCOSMIUS, new species. 



Chiton small, back high but rounded, surface without eyespots; the 

 surface variegated with white and sage-green with a tendency to 

 white spots on the posterior edge of the intermediate valves as in 

 C. dentiens, the interior apple-green; anterior valve with 10 slits, 

 somewhat more than semicircular, obliquely decussated with extremely 

 line striae, which on the intermediate valves give an effect of divari- 

 cation, this sort of sculpture covers the whole shell ; posterior valve 

 with 9 slits, and a low blunt mucro in front of which the valve is 

 depressed; girdle white or maculated with white and gray, covered 

 densely Avith flattish lozenge-shaped, pavement-like scales; inter- 

 mediate valves with 1 slit at each end, the lateral areas feebly 

 marked without distinctive sculpture, the sutural laminae narrow, the 

 jugal sinus very shallow, defined by a slight notch at each end. 

 Length, 10; width, 5.5; height, 3.3 mm. 



Hahitat. — Magdalena Bay, Lower California, C. R. Orcutt. Cat. 

 No. 218194, U.sTn.M. 



The coloration of the specimens in hand is especially neat, though 

 doubtless in a large number the variations would be extreme. 



ISCHNOCHITON VENEZIUS. new species. 



Chiton small, .warm yellow-brown with a whitish " bloom," the 

 girdle mottled with brown and white, covered with a pavement-like 

 coating of minute rounded scales; anterior valve with 14; posterior 

 with 12; and the intermediate valves with 1 slit at each end; 

 anterior valve nearly semicircular, with over 20 radial rows of small 

 pustules, for the rest covered with a very minute oblique decussation ; 

 posterior valve smaller, with mucro low and slightly behind the cen- 

 ter, the posterior tract decussated minutely and with a few scattered 

 pustules near the margin, the central area reticulate; intermediate 

 valves mucronate, minutely decussate; pleural tracts with fine low 

 axial threading and punctate interspaces; lateral areas with 2 or 3 

 somewhat irregular radial rows of pustules on a minutely decussated 

 ground. Length, 7 ; width, 3.5 ; height, 2 mm. 



Hahitat. — Near Venice, Los Angeles County, CalifoKnia, Uni- 

 versity of Southern California. Cat. No. 216792, U.S.N.M. 



This is one of the most elegant of the smaller species of the coast. 

 The jugal sinus is straight edged and the sutural laminae narrow. 



7 CHAETOPLEURA LACTICA, new species. 



Cliiton small, cream-colored, often maculated with pale green, with 

 high almost carinate back, the girdle spongy with a few small spin- 

 ules and sparse hairs on a leathery basis; anterior valve with 8 or 9 



