Shell of medium size, nucleus lost, remaining whorls 14, surface chalky and eroded near apex, near the aperture there are thin periostracal remnants. Earliest whorls with a single projecting carination at 1/3 the distance from the anterior suture, persisting on later whorls as the single strong carination at 1/4 the distance above the suture, the area below beveled in toward the suture. On the penultimate whorl there are in addition 4 weakly defined spiral cords and fine irregular spiral striae throughout. The base is defined by an angularity, just below which the suture is laid, producing a deeply indented suture. Base nearly flat, with fine, scarcely perceptible spiral striae. Growth line trace producing a broad sinus, in nearly central position on the whorl. Aperture rounded quadrate, lip and columella thin, parietal area glossy. Color tan, with irregular dark markings along the growth line trace. Height, 48.4, diameter, 13.4 mm.

Turritella parkeri was illustrated by Parker (1964, pl. 7, fig. 1, "Turritella sp.") as a species characteristic of deep northern basins and troughs in the Gulf of California, 230-1400 meters in depth, but I am unable to determine the station of his specimen. It is, however, a species found at greater depths than other eastern Pacific Turritella. It is evidently related to T. cooperi Carpenter, 1864, and T. mariana Dall, 1908, 2 eastern Pacific species in which the single prominent carination near the base of the early whorls persists in the same position on the adult whorls. Turritella parkeri is broader than both of these species and bears a single prominent carination on mature whorls, while both T. cooperi and 7". mariana develop 2 or more strong carinations per whorl. The early sculpture of T. parkeri is illustrated in Fig. 38. The largest of the LACM paratypes measures 57 mm in length (nuclear whorls lost), 16 mm in diameter. Turritella parkeri is named for Robert H. Parker, whose 1964 paper is an important source of ecological data for many Eastern Pacific species.

Type Locality: West of Espirutu Santo Island in Bahia de La Paz, Baja California, 24° 24.3' to 24° 25.6' N, 110° 23.7' to 110° 25.5' W, 45-65 fathoms, R/V Thomas Washington (Scripps Institution of Oceanography) station MV 68-1-29, 12 January 1968, 74 specimens, 15 in fresh condition.
Type Material: Holotype, LACM 1401, 27 paratypes, LACM 1402; 30 paratypes, Scripps Collection. Two paratypes each, AMNH, ANSP, CAS, MCZ, SBM, SDNHM, SU and USNM.
Referred Material: AHF bottom sample station 247, 3 miles off San Gabriel Bay, Espiritu Santo Island, 80 fathoms, 3 specimens (Fig. 38); Shasky Collection (Redlands, California), off east side, Espiritu Santo Island, 40-90 fathoms, Ariel Expedition, 1960, 4 specimens.