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sis, undique delicate decussatis, interstitiis quadratulis ; apertura ovato-lunari,. 

 labro paullum incrassato, margine minute crenuluto, supra late excavato. 

 Loug. 5, lat. 3"50 mm. 



Hab. Gulf of Oman, lat. 24° 58' N., long. 56° 54' E., 156 fathoms. 

 Only two species, of which the best known is K. cancellaris, A. Ad., from 

 Corca and Japan, have hitherto been described of this genus, and to these we 

 venture now to add a third. Undoubtedly, they have a close family affinity to 

 each other : the K. sympiesta may be known by its particularly obese and com- 

 pressed form and tumid body-whorl ; the umbilicus i9 deep and the outer lip 

 minutely crenulate on the margin. 



Judging alone from conchological grounds, the animal being absolutely un- 

 known, we should assign to this genus a place near Ackeon, Montft., and not, 

 as suggested by some authors, consider it one of an outlying group of the Pyra- 

 midellidoe. Indeed, were it not for the total absence of the columellar plicae, 

 we should regard it as a member of the genus just mentioned (Actaon). 



CYLICHNA (MNESTIA) BIZONA, A. Adams. (Pi. D. fig. 17.) 

 Bulla (Cylichna) iizoua, A. Ad. in Sowerby, Thes. Conch, pt. 11, vol. ii.,. 



p. 595, pi. cxxv.,fig. 148. 

 Hub. Gulf of Oman, Maskat, 15 fathoms. 



A large local form (alt. 7, diam. 3 mm.), which we figure, as contrasting with 

 the Chinese examples in the Cumingian collection and with others. It is a 

 species of wide distribution, being reported from China, Singapore, Fiji, and 

 Torres Straits. 



CYLICHNA JECORALIS, sp. n. (PI. D. fig. 18.) 

 C. testa oblongo-cylindrica, delicata, apud basim paullum effusa, apice imper- 

 forate, plicato, subhyalina, superficie lasvi, nitida, antice posticeque spiraliter 

 striata, pallide livido-olivacea ; apertura pyriformi, supra angusta, intus 

 cinerea, labro paullum eft'uso, tenui ; columella obscurissime plicata. 

 Alt. 11, diam. 5 mm. 

 Hab. Persian Gulf , Gulf of Oman, Maskat, 15 fathoms. 



Without a knowledge of the anatomy of these small species of Tectibranchs, 

 it is often mere guesswork assigning them to generic positions. This species, 

 however, seems best located in Cylichna, in our opinion. It is a delicate^ 

 moderate-sized species, of a peculiar hepatic tint, this suggesting the proposed 

 specific name. 



RETUSA OMANENSIS, sp. n. (PI. D. fig. 19.) 

 R. testa parva, cylindrica, albo-lactca, subhyalina, tenui, supra, truncatulo 

 apice fere immerso ; anfractibus 3, supra excavatulis, marginibus apud 

 suturas acutis. prominulis, superficie omni spiraliter sub lente delicatissime 

 striata ; apertura postice latiore, oblonga, antice angusta, labro recto, ad 

 basim rotundata ; columella obscure uniplicata, margine paullum incrassato. 

 Alt. 4, diam. 175 mm. 



Hab. Gulf of Oman, lat. 24° 58' N., long. 56° 54' E., 15G fathoms. 



