E42 PROCEEDINGS OF THE NATIONAL MUSEUM VOL. 113 
Eurhinocricus williamst Hoffman, Proc. Biol. Soc. Washington, vol. 68, p. 35, 
1955. 
Canal Zone, many specimens from following locations: Barro Col- 
orado Island, Frijoles, Monte Lirio, Fort Sherman, 1923, O. F. Cook 
and H. F. Loomis; Barro Colorado Island, 1955 and 1956, C. W. and 
M. E. Rettenmeyer, and 1958, E. M. and H. F. Loomis; Cruces Trail, 
Madden Dam, 1955, Hartig and Johnson; Pifia area, 1958, H. F. 
Loomis. 
Panama, many specimens collected by O. F. Cook and H. F. 
Loomis or individually in 1923 from Alahjuela and Juan Dias. 
This is probably the most common milliped in the region of the 
Canal Zone. Abundance of specimens was indicated by Chamber- 
lin for both of his species, but the descriptions of them are only par- 
tially comparable with each other although each apples rather well 
to the present specimens. In view of this and that no illustrations 
of either species were given and that no other species of Rhinocricus 
has been found in the present collection, it is believed that Cham- 
berlin was dealing with but a single species. 
Descriptive NoTE: The prominent lateral ridge of segment 2, 
an outstanding character of the species, is rather variable as shown 
in figure 6k-l. Transverse sulcus of segments strongly impressed 
across dorsum; pores large, followed by a fine impressed sulcus. 
Last segment with apex thick, definitely exceeding anal valves, 
which are flattened on the sides with margins continuous and not 
separately raised. Preanal scale large, thick, triangular, not quite 
half as long as wide, apex not acute but rather sharply rounded. 
Gonopods as shown in figure 7a, in which the median plate, variable 
in width in this species, is seen in its wide phase; posterior gonopod 
as shown in figure 7b. Male legs 3, 4, and 5 with coxae raised into 
quite thin transverse lobes, subconic on leg 3 but becoming increas- 
ingly broader on legs 4 and 5; last joint of legs from third pair to 
behind middle of body inflated beneath. 
Family Spirostreptidae 
Genus Orthoporus Silvestri 
Orthoporus Silvestri, Boll. Mus. Zool. Anat. Comp. Univ. Torino, vol. 12, No. 283 
D.10, 1897. 
Orthoporus canalis Chamberlin 
Orthoporus canalis Chamberlin, Proc. Biol. Soc. Washington, vol. 38, p. 38, 1925. 
Canal Zone, many specimens from following localities: Barro Col- 
orado Island, June 6, 1923, O. F. Cook and H. F. Loomis; Monte 
Lirio, June 8, 1923, O. F. Cook and R. D. Martin; Pifia area, March 
18, 1958, H. F. Loomis. 
