THOMPSON: Humboldtiana from Chihuahua and Texas 95
Table 9. Humboldtiana hogeana Martens, 1882. Measurements in mm of the lectotype and the mature paralectotype a.
 H W AW AH Whorls H/W AW/W AH/H AW/AH
Lectotype 26.4 32.8 17.7 21.6 3.9 0.80 0.54 0.82 0.82
Paralectotype 22.8 29.4 16.6 20.2 3.8 0.78 0.56 0.89 0.82
on the growth wrinkles. The streaks may be continuous, or they may be broken into shorter segments. The streaks are more numerous and crowed on the apex to the extent that they obscure the light brown ground color. The interior of the aperture is light brown with a whitish tinge and is banded. The peristome is colored the same as the ground color. The parietal callus is thin and hyaline. There are 1.4-1.5 rather low embryonic whorls. The first embryonic whorl is 4.0-4.1 mm wide transverse to the initial suture. The embryonic whorls are sculptured with very fine transverse striations. The subsequent whorls are sculpture with distinct but fine incremental striations and wrinkles that are continuous from the suture into the umbilicus. Granular sculpture is completely absent on the embryonic and the post-embryonic whorls. The umbilicus is rimate (Fig. 73). The whorls regularly increase in size along the middle band until the last quarter whorl and then rapidly descends to the aperture. The upper lip inserting on the lower band. The plain of aperture lies at 41-45 to the shell axis (Fig. 71). The aperture is broadly oval and is about 1.15 times as wide as high. The peristome is very narrowly reflected along the upper, outer and basal lips, and broadly reflected over the umbilicus.
Measurements of the holotype and four paratypes are given in Table 10.
Anatomy (Figs. 76-77). Three specimens were dissected (UF 21325). The genital atrium is moderately slender and is 4 mm long. The penis is 8 mm long and is clavate in shape with the epiphallus entering the apex eccentrically The penis contains a stout verge that extends to about the middle of the penis (Fig. 77). The inner wall of the penis has a girdle of 5-6 heavy folds along its upper half. The folds become smaller and sub-equal in size near the base of the penis. The stout penis retractor muscle originates on the middle of the inner wall of the lung, and inserts on the apex of the penis. It is slightly longer than the penis and forms a narrow sheath around the base of the epiphallus. The epiphallus is moderately stout, uniformly wide, and is about as long as the penis. Its interior is lined with 4-5 longitudinal folds. The flagellum is very long and slender. It is about seven
times the combined length of penis + epiphallus, 115 mm. long. The lower vagina is moderately short, and bears four unequal sized dart-sacs, of which ds, is the largest and ds4 is the smallest. The dart-glands form a ring around the middle vagina immediately above the dart-sacs. The free vagina is about 3-4 mm long. The spermathecal duct is very long, being about 110 mm long. It is about as stout as the epiphallus, is about as long as the flagellum, and is about 2.5 times the length of the uterus-prostate. The spermathecal duct bears a caecum that diverges at about 0.8 of the distance above the base of the duct. The caecum is short and is less than half the length of the remaining spermathecal duct + spermatheca. The spermathecal duct gradually expands into the narrow sack-shaped spermatheca.
Type locality. Chihuahua, Sierra Santo Domingo, 4 km west-southwest of Francisco Portillo (2836'N, 10554'W), 1970malt. Holotype: UF21324; collected 27 November, 1970 by Fred G. Thompson. Paratypes: UF 21325 (3), ITCV (2); same data as the holotype.
Francisco Portillo is a mining town located about 21 km ESE of Cd. Chihuahua. It is reached by driving 13 km SE of the city on Hwy. 45 and then ENE on a microwave tower road. The village of Francisco Portillo is 9 km further ENE on the road. Snails were collected behind the Mina Vieja lead-silver mine, approximately 4 km WSW of Francisco Portillo. In 1970 Francisco Portillo was known as Tulalia.
Distribution. Known only from the type locality.
Ecology. Snails were collected on limestone ledges where they were aestivating beneath and among leaves of a large species of Agave that was growing on the face of the ledge. The lowermost Agave leaves form a rosette that is adpressed against the rock, which is cooled by the live plant and provides shelter from predators. Other vegetation in the immediate vicinity consisted of sparse growths of xeric shrubs. The area was very dry at the time of the collection.
Remarks. This elegant appearing snail is unlike any other Humboldtiana. The combination of the glossy, brightly colored shell, the fine transverse striations on