6 PROCEEDINGS OF THE NATIONAL MUSEUM VOL. 125 
north of the Arkansas River in Arkansas, Missouri, and Oklahoma; 
the eastern slopes of the Sierra Madre Oriental in Veracruz. Obviously, 
this fragmented range must at some time have been continuous. 
A discussion of possible migration routes and the evolution of the 
genus follows the systematic accounts. 
Key to the Species of Genus Pterodrilus 
1. Dorsal projections present:.34. 6 i ndes vs ool se ot 5s OM ee eee 3 
Dorsal projections absent, prosomite of segment VIII raised....... 2 
2(1). Dorsal ridges on segments I-VIII..... P. missouriensis, new species 
Dorsal ridge on segment VIII only....... P. choritonamus, new species 
3(1). Dorsal projections on raised prosomite of segment VIII only......... 4 
Dorsal projections on raised prosomites of other segments in addition to 
segmenity WI ein el Se ce Peale le ee Baar ote, Sree 6 
4(8). Segments I-VIII with ridges............... P. cedrus, new species 
Segments other than- VIII without ridges. ...-2 .s:.23: av sei oe 5 
5(4). Fanlike dorsal projection of segment VIII with 5 prongs; bursa small, 
ejaculatory, (duct plone mia. acest -ialcmerelene ene P. hobbsi, new species 
Fanlike dorsal projection of segment VIII with 4 prongs; bursa large, 
ejaculatory duct shorten cece aieteenenc mieten eee ee P. mexicanus Ellis 
6(3). Two finger-like dorsal projections on segments II-VII, 5 on segment 
AV TTT i satya Caged ateestie eh ne oncmer oe’ Sach eS banat payee hes lees P. distichus Moore 
Fanlike dorsal projections on segments III-V, VIII................. ef 
7(6). Fanlike dorsal projection lacking on segment II...P. alcicornus Moore 
Fanlike dorsal projection present on segment II. . . P. simondsi, new species 
Pterodrilus alcicornus Moore 
Figures 1, 10 
Pterodrilus alcicornus Moore, 1895a, pp. 450-453.—Pierantoni, 1912, p. 25.— 
Ellis, 1919, p. 254.—Goodnight, 1940, pp. 58-50; 1941, p. 468.—Hobbs, 
Holt, and Walton, 1967, pp. 61-62. 
TYPE-SPECIMENS.—The material from Johns River, Watauga 
County, N.C., upon which Moore based this species, has not been 
found among Moore’s collections now in the U.S. National Museum 
nor among the collections of the Academy of Natural Sciences of 
Philadelphia. The species is distinctive, subsequent identifications 
are not disputed, and no neotype has been designated. 
DiaGnosis.—Dorsal ridges on segments II-VIITI; those of III-V, 
VIII bearing fanlike dorsal projections; bursa ovoid, less than 4 body 
diameter in length; ejaculatory duct of medium length; length of 
spermiducal gland about 3 times its diameter; prostate subequal in 
diameter to that of spermiducal gland and % to % its length, histo- 
logically differentiated from the latter; spermatheca longer than body 
diameter, bending dorsad to gut, ectal duet long and narrow, bulb 
clavate, ental process absent. 
