160 riiOCEEDINGS OF THE M^Ui-ACOLOGICAL SOCIETY. 



DESCRIPTIONS OF FOUR NEW SHELLS FROM THE PERSIAN GULF 

 AND BAY OF ZAILA. 



By G. B. SowERBY, F.L.S., etc. 



Read June Sth, 1894. 



PLATE XII. Figs. 20, 23, 25, 26. 



1. Cancellaeia paucicostata, n.sp. PL XII. Fig. 26. 



Testa anguluta, utrinque conica, vix umbilicata, pallide fulva, 

 obscure f iisco fasciata ; spira conica, gradata, mediocriter elevata ; 

 anfractus 6, convexi, embryonales la}ves, scquentes obtuse anguluti, 

 longitudinaliter costati, liris numerosis confertis angustis alterne 

 crassioribus eximie lamcllatis spiraliter sculpti ; anfractus ultimus 

 costis paucis irregularibiis instructus ; apertura latiuscula, sub- 

 trigonalis, labrum leviter arcuatum, fusco tinctum ; columella 

 rectiuscala, triplicata. Long. 17, lat. 11.50 mm. 



Hah. — Persian Gulf. 



An exquisitely sculptured shell, in which the angle of the body- 

 whorl is lower than in the prevailing forms of the genus. The 

 ribs on the body-whorl are few and irregularly placed. It would 

 be difficult to assign the sectional or sub-generic position of this 

 species, according to Dr. Jousseaume's arrangement. In form it 

 seems intermediate between £uclia, H. and A. Adams, and Scalptia, 

 Jousseaume ; it has also some affinity with Trigonostoma, Blainville, 

 as represented by C. costata, Gray, though it wants the umbilicus. 



2. Ancilla (Monoptygma) unidentata, n.sp. PL XII. Fig. 20. 

 Testa oblongo subovata, crassa, polita, nitens, pallide fuscescens, 



hie illic castaneo strigata, postice castaneo latifasciata ; spira exserta, 

 obtusiuscula, callosa; apertura oblonga, postice angustiuscula, antice 

 latior, truncata; labrum Iseve, crassiusculum ; columella antice le^-iter 

 contorta, plicata, postice callosa, plica i;nica dentiformi instructa. 

 Long. 6, lat. 3 mm. 



Ilab. — Bay of Zaila. 



A bright shining little shell, of which tlie spire is covered with a 

 dark -brown enamel. It forms the second recent species of Lea's genus 

 Monoptygma, characterized by a tooth-like plica above the middle of 

 the columella. 



3. Xassa Zailensis, n.sp. PL XII. Fig. 25. 



Testa acuminato-ovata, crassa, rugosa, griseo-albida, nigTO-fusco 

 fasciata; spira elata, acuta; anfractus 8, convexi, spiraliter subtilissime 

 striati, costis numerosis nodulosis albo-articulatis instructi, nodulis 

 obtusis, confertis ; anfractus ultimus veutricosus, supra sulca latiuscula 

 divisus; apertura subovata, intus costata, nigro-fusco fasciata, canali 

 brevissimo ; labrum polituiu, latiusculum, album, fusco pictum ; 

 columella brevis, alba, plicata, antice contorta. Long. 15, maj. lat. 

 8 mm. 



