256 MISS JANE DON-ALD 0^ THE GENERA [May 1 899, 



whose length =25| mm., width = 9| mm. A larger but more 

 weathered specimen, which also has the apex broken, leavino- nine 

 whorls, measures 33 mm. in length and 10 mm. in width. 



Locality and Horizon. — Durness Limestone, Sutherland. 



ECTOMAEIA GIRVANENSIS, Sp. nOV. (PI. XXI, fig. 5.) 



Description. — Shell elongated, turreted, composed of more than 

 seven gradually increasing whorls. Ornamentation consisting of 

 two strong keels, the uppermost of which is situated near the middle 

 of the whorl and the other below, a short distance above the suture. 

 On the body-whorl there is an additional keel below, and there is 

 also a fine thread above at the suture. The two middle keels are 

 about equal in strength ; the space above them is the widest, and 

 that below is the narrowest. Lines of growth very indistinct, 

 apparently sloping backward above the strong keels. Aperture 

 unknown. 



Eemarks. — In Mrs. Gray's collection, Edinburgh, there is one 

 large specimen of this species and a fragment of a smaller specimen 

 which is most probably identical with it. The surface of the former 

 is much worn, and the latter is merely an internal mould. 



Resemblances. — This species resembles E. pagoda and its 

 varieties, but is distinguished from them all by being a larger and 

 more solid-looking shell. From the type of E. pagoda it further 

 differs in the spaces between the keels, being of more unequal 

 width, though it agrees with this form in the keels being about 

 equal in strength, whereas in the var. orientalis the central keel is 

 much the strongest. The character of the ornamentation approaches 

 most nearly that of Murcliisonia Adelina, Billings, but that shell 

 increases more slowly and is of greater size. 



Dimensions. — The specimen figured here (PI. XXT, fig. 5) 

 is embedded in the matrix, and shows only the seven lower vihorls ; 

 these measure 30 mm. in length and 10 mm. in width. 



Locality and Horizon. — In rocks of Llandeilo [Lapworth] 

 age at Minuution (Ayrshire). 



ECTOMARIA (?) EXIGUA, Sp. nOV. (PI. XXI, fig. 6.) 



Descriptio n. — Shell small, slender, turreted. Whorls more than 

 four, high in proportion to the width, increasing very gradually. 

 Ornamentation consisting of two strong keels, the uppermost of 

 which is situated near the middle of the whorl, and the other a little 

 below ; there is also a fine thread on the body-whorl which is visible 

 immediately above the lower suture on the penultimate whorl. The 

 surface of the whorl is slightly adpressed at the suture. Lines of 

 growth and aperture unknown. 



Remarks. — There is but one specimen of this species in the 

 collection of Mrs. Gray, and it is very imperfect. I therefore refer it 

 with some hesitation to this genus, to members of which it bears 

 considerable resemblance ; nevertheless, better preserved examples 

 may prove it to have a slit in the outer lip, in which case it would 

 have to be referred to Murcliisonia. 



