180 BULLETIN OF THE 



Prophysaon fasciatum, Cockerell. 



Length (in alcohol) 19 mm. Mantle black, with indistinct pale subdorsal 

 bands, — an effect due to the excessive development of the three dark bands of 

 the mantle. Body with a blackish dorsal band, commencing broadly behind 

 mantle and tapering to tail, and blackish subdorsal bands. No pale dorsal 

 line. Keticulations on body squarer, smaller, more regular, and more sub- 

 divided than in P. Andersoni, Cooper. Penis sac tapering, slender. Testicle 

 large. Jaw ribbed. (Cockerell.) 



Prophysaon fasciatum, Cockerell, The Nautilus, 1890. 



Prophysaon fasciatum, W. G. Binney, 3d Suppl. to Terr. MolL V., p. 209, Plate 

 VII. Eig. A. 



Cceur d'Alene Mountains, Idaho; a species of the Central Eegion. 



This species is described by Mr. Cockerell as distinct from Andersoni, with 

 which I have formerly confounded it. (2d Suppl. to Vol. V., p. 42.) It has a 

 dark band on each side of the body, running from the mouth to the foot, and a 

 central dorsal dark band. To this must be referred the descriptions of animal, 

 dentition, jaw, and genitalia formerly published by me as of Andersoni. 



I am indebted to Mr. Theo. D.- A. Cockerell for a figure and description of 

 this species. The former is given on Plate VII. Fig. A, while the latter is 

 given here in the words of Mr. Cockerell, whose name must consequently be 

 associated with it as authority. 



The animal extends itself into a long, cylindrical worm-like bodj'^ with ob- 

 tuse ends ; the mantle is covered with minute tubercles. 



Jaw low, arcuate, ends blunt ; with numerous (over 15) irregularly devel- 

 oped broad, stout ribs, denticulating either margin. 



The lingual membrane has 30-1-30 teeth, with about 12 perfect laterals. 

 Centrals tricuspid; laterals bicuspid; marginals with one long, stout, oblique 

 inner cutting point, and one outer short, blunt, sometimes bifid cutting point. 

 Resembling that of P. Hemphilli. Another membrane has 50-1-50 teeth. 



Mr. Cockerell describes the penis sac as tapering; in specimens examined by 

 me it is cylindrical, as in Hemphilli. 



The internal shell is thick, easily extracted without breaking. 



Phenacarion, Cockerell.^ 



Animal limaciform, cylindrical, blunt before, tapering behind ; tentacles 

 simple; mantle large, anterior, pointed behind, concealing a delicate, thin, 

 subrudimentary calcareous shell-plate, easily fractured; no longitudinal fur- 

 rows along the margin of the foot; a caudal mucus pore; no distinct locomo- 

 tive disk; external respiratory and anal orifices on the right anterior margin 



' Phenax = an impostor, and Arion. Cockerell, The Nautilus, Vol. III. p. 126, 

 March, 1890. 



