556 MISS JANE DONALD ON THE GENERA [Nov. I906, 



2. Bowdeni Subsection. — Elongated shells; eight to twelve whorls, less 



angular than in the preceding subsection. Type, L. Bowdeni, Safford. 



3. Cicelia Subsection. — Differs from 1 in having a inueh more elongated 



spire, and from 2 in having more numerous and more sharply-angular 

 whorls. Type, L. cicelia, Billings. 



4. Serrulata Subsection. — Distinguished from 1 by the plate-like 



extension and wavy character of the central keel of the sinual band. 

 Type, L. serrulata, Salter. 



B. Bicincta Section. — Lines of growth curving very slightly, or not at all, 



backward to the sinual band ; sinus very shallow. 



1. Bicincta Subsection. — Surface-markings fine, generally regular, 



sharply raised and closely arranged. Type, L. bicincta, Hall. 



2. Tubulosa Subsection. — Similar to the preceding, but the lines of 



growth are much stronger, lamellose, and imbricating, particularly on 

 the band. Type, L. tubulosa, Lindstrom. 



3. Imbricata Subsection. — Relatively elevated small shells, with coarsely- 



lamellar imbricating lines of growth, which indicate a very oblique 

 aperture below the sinual band. Type, L. imbricata, Lindstrom. 



4. Holmi Subsection. — Lines of growth similar to those oi L. bicincta, 



but having the obliquity below the band of those of the imbricata 

 subsection. Type, L. Holmi, Lindstrom. 

 5.. Helicteres Subsection. — Agrees in all respects with the bicincta sub- 

 section, excepting that the last whorl or two are free. Type, L. helicteres, 

 Salter. 



C. Robttsta Section. — Shells short ; whorls more or less convex, ventricose, 



scarcely angular even at the sinual band, which is distinctly trilineate. 

 Base usually ornamented by rather slight spiral keels. Lines of growth 

 indicating a wide but not very deep sinus in the outer lip. Type, 

 L. ohioensis, James. 



D. Trochonemoides Section. — Like Trochonema, except that there is a 



distinct sinual band. Differs from the usual types of Loplwspira in the 

 relatively-depressed form, large umbilicus, thick shell, and oblique 

 aperture. Type, L. trochonemoides, Ulrich. 



These divisions are, perhaps, hardly all of the same value ; and 

 they may not all stand ultimately, but they are useful in the 

 present state of our knowledge. The British species with which I 

 am acquainted number fourteen (and there is also one variety) : 

 four of these have been previously referred to the genus Miirchisonia. 

 Some greatly resemble American species ; but only one, Loplwspira 

 bicincta, Hall, can be identified with certainty. Many have the sur- 

 face so imperfectly preserved, occurring merely as internal or external 

 moulds, that it is difficult to make accurate comparisons. They are 

 referable to three of the sections, and may he tabulated thus : — 



A. Pebangulata Section. 



1. Perangulata Subsection. — L. gyrogonia (M'Coy) ; L. excavata, 

 sp. nov. ; L. variabilis (Don.) ; L. borealis (Don.) ; L. trispiralis, sp. nov. ; 

 L. instabilis, sp. nov. : L. Seclgwickii, sp. nov. 



3. Cicelia Subsection. — L. (?) angidocincta (Salt.) ; L. ferruginea, sp.nov. 



B. Bicincta Section. 



1. Bicincta Subsection. — L. bicincta (Hall), var. scotica, nov. ; L. bclli- 



carinata, sp. nov. 



2. Tubulosa Subsection. — L. cyclonema (Salt.) ; L. pulchra (M'Coy). 



C. Bobusta Section. — L. subglobosa, sp. nov. 



Range. — The British species range from the Durness Limestone 

 up into the Wenlock Limestone. Upwards of fifty species have been 



