I'art 2] K i.isixA AND A(i.isiuin:s. 77 



Aci.isiNA Acn ri.ATA Doiiald. (PI. VI, tiic- ^) 



Aclisiiut ariritlata Donald, 1K98, itp. cit. p. 59 & pi. iv, rijj^s. I (5. 



Iicmarks. -li^ addition to the .specimens previously I'ecorded, 

 there aiv twenty in Mr. Jolni Sniitli's eolleetion, six of whieli have 

 tlie jM-otoeoneli ])reserved : it is like tliat Hi^ured (op. cit. pi. iv, 

 tii^rs. {\a-(\c). As the shell in the Hunter-Selkirk Colleetic.n, from 

 whieh these dniwini^'s were made, has heen destroyed hv lire, it is 

 esjK'eially fortunate that more examples are availahle! Two of 

 the sj)eeimens not only have the protoeoneh raised, hut the three 

 hii^her whorls of the spin* are remarkahly drawn out and loosely 

 eoiled ( 1*1. VJ, til,^ (1). They are all froin Dykes, Kilhirnie: that 

 in the Hunter-Selkirk Collection was from Law, Dalrv. Both 

 localities are in the Lower Limestone Series. 



Holoty))e. O/). t'if. pi. iv, tig. 4. Young Collection, Kelvin- 

 grove Museum, (ilasgow. 



Locality and horizon.- (iillfoot, Carhd<e f Lanarkshire ), in 

 the L'^j)))er Limestone Series. 



Aci.isiNA r MiF/nvoLVA, sp. nov. { PI. \I, ligs. 7 & S. ) 



Diagnosis. Shell elongated, turriculated, com))o.sed of more 

 than nine gmdually increasing whorls. Whorls angular near the 

 middle. Hat or slii^ditly concave ahove. Hat or harely convex helow. 

 Ornamentation consi.sting of a strong thread on * the angle with 

 three helow, the lowest of whieh is oidy .seen on the hodv- whorl 

 and at the suture of the anterior whorls'of the si)ire ; ahove, there 

 is a strong thread with a Hner one ch)se to it, and on one of the 

 whorls there is an indicatidn of a still liner thread ahove. Sutures 

 deep. Ba.se rather Hat. Ccdumella nearly str.iii,^ht. Apex and 

 aperture miknown. 



H^'inarks. This s])ecies is most iikc A. xiihrintii/otd, hut dilTcrs 

 in heing more slendei-, and in having fewer and stronger ornament- 

 ing threads helow tiie angle, while there is an additional liner one 

 ahove. 



it IS imi><»ssil)lf to place the species with certainly, as neither 

 protoeoneh, ajH-rture, nor lines of growth are preserved": it is there- 

 fore only referred to Ar/ifsi/Ki j)rovisionallv. 



I have met with six specimens, three of which are verv >mall, 

 and one is also more slender. This last is in the late Dr. .Ldm 

 Young's collection, and occurred in the Cjiper Limestone Serii's at 

 <llencai-t. The other two helong to Mr. J. Smith, and were also 

 fomid in the I'pper Limestone Series. The remaining three are of 

 irreater si/e, i>therwise they exhihit similar characters in form and 

 '•rnamentation. They are fmm the Lower Limestone Series, when' 

 it is not unusual for siu-cimens of nmch larger dimensions to occur. 

 One has seven whorls in a length of 11 •.') millimetres, and the 

 UM-eatest width =10 mm. Originally it must have Ix'cn more 

 elongated, for it is compressed upwanls, causing the lower whorls 

 to 1m' hroader and slu.rter. This example is fn)m Haidvcnd ( Lanark- 

 shire). Only the aJiterior portions of tji.- (ith.T t\v.. .-xist. consistiui^ 



II 2 



