Yol. 55.] ECTOMAEIA AND HOKMOTOMA. 271 



than eight whorls. Whorls increasing gradually, convex, smooth, 

 with the exception of a raised thread just below the suture. Sinual 

 band situated below the middle of the whorl, level with the surface 

 or but slightly depressed, limited by a raised thread on each side. 

 Lines of growth fine, sharp, curving strongly backward to the band 

 above, and still more obliquely forward below, not visible on the 

 baud itself. Aperture imperfectly known, probably subovoid. 



Resemblances. — This species may be distinguished from H. 

 Salteri by its greater size, apparently higher whorls, the lower 

 position of the sinual band, and by having a strong raised thread 

 below the suture instead of merely a swelling. It resembles that 

 species, however, in the structure of the band, the smoothness of 

 the whorls, and the character of the lines of growth. 



Dimensions. — The best-preserved specimen is figured in 

 PI. XXII, fig. 10 ; it is crushed and imperfect, both apex and 

 base being broken ; the eight existing whorls measure 40 mm. in 

 length, and the penultimate whorl measures 10 mm. in width. 

 Three other individuals are associated with this, but they are mere 

 casts, and are too imperfect to be identified with certainty. 



Locality and Horizon. — All the examples are in Mrs. Gray's 

 collection, and occur in rocks of Middle Llandovery age [Lapworth] 

 at Woodland Point. 



EXPLANATION OF PLATES XXI & XXII. 

 Plate XXI. 



Figs. 1 & 2. Ectomaria pagoda (Salt.) var. Peackii nov. Fig. 1. Laterally 

 compressed, X2. Fig. 2. Fragment of another specimen, X 2. 

 Durness. G-eol. Surv. Coll., Edinburgh Museum. 

 3 & 4. E. pagoda (Salt.) var. orientalis nov. Fig. 3, x2. Fig. 4. 

 Aperture of another specimen, x2. Durness. Geol. Surv. Coll., 

 Edinburgh Museum. 



Fig. 5. E. girvanensis, sp. nov. Specimen partially embedded in matrix, X 1^. 

 Minuntion. Gray Coll., Edinburgh. 

 6. E. f?J exigua, sp. nov., x4. Minuntion. Gray Coll., Edinburgh. 



Figs. 7-11. Hormotoma Salteri, Ulr. & Sco. Fig. 7, x2. Fig. 7 a. View 

 of base, x2. Fig. 7 h. Side view of body-whorl, x2. Fig. 8. 

 Another specimen on tlie same piece of rock, X2. Durness. Geol. 

 Surv. Coll., Edinburgh Museum. Fig. 9. Front view of specimen, x2. 

 Fig. 10. Back view of another, nat. size. Fig. 11. View of aperture 

 of same, nat. size (probably the var. nitida, Ulr. & Sco.), for com- 

 parison, from the Trenton formation, AUumette Island. British 

 Museum (Nat. Hist.). 



Fig. 12. H. (1 ) gmcilUina (Salt.). Nat. size. Durness. Museum of Pract. 

 Geol., London. 

 13. H. (1 ) dubia, sp. nov. Nat. size. Durness. Museum of Pract. Geol., 

 London. 



Figs. 14-17. H. cingulata (His.). Fig. 14. View of specimen partially embedded, 

 nat. siz3. Aymestry. Museum of Geol Soc, London. Fig. 15. Front 

 view of type of Terebra (i) sinuosa, Salt., nat. size. Mocktree. Lewis 

 Coll., British Museum (Nat. Hist.). Fig. 16. Portion of whorl of 

 specimen showing lines of growth, slight angularity above the suture, 

 and apparent depth of sinus, X 2. Grindrod Coll., Oxford University 

 Museum. Fig. 17. Portion of whorl of another specimen, showirg 

 lines of grovtth and some of the spiral ornamenting threads, x2. 

 Knapp Lane, Leibury. Piper Coll., British Museum (Nat. Hist.). 



