1879.] C.AECID.E OF THE ' CHALLENGER ' EXPEDITION. 811 



The septum is nearly flat, and projects so slightly as to be barely 

 visible from the side. 



This species may possibly be only a variety of C. subflavum; but 

 the difference in the septum seems to individualize it. 



TJL /zo 11. Cecum microcyclos, n. sp. 



St. 186. Sept. 8, 1874. Flinders Passage, Cape York. 7 fms. 

 Fourteen specimens. 



Testa subconica, elongata, arcuata, flavescens, nitidissima, sub- 

 opaca, annulis multis parum expressis cincta, aperturum versus 

 paulo dilatata. Apertura haud obliqua, nee contracta, haud 

 marginata ; septo subangulato, submucronato, aliquando bimu- 

 cronato. 

 Length 2 mm. Breadth 03 mm. 



This beautiful species is long in proportion to its breadth ; it is 

 conical, rather bent, yellowish, very glossy and nearly opaque. The 

 sculpture consists of numerous small rings, very close-set and slightly 

 prominent. It is sometimes as smooth as C. succineum, from 

 which it differs in its greater length, its more conical form, and the 

 shape of its septum. The mouth is normal in its relation to the 

 axis ; it has no marginal ring ; and the shell expands towards it 

 regularly without any contraction. The septum is somewhat pointedly 

 subangulated, presenting occasionally two or three very similar pro- 

 tuberances. 



12. Cecum elegantissimtjm, Carp. 



Feb. 10, 1873. OffTenerife. 70 fms. Six specimens. 

 These specimens present slight differences, but belong unques- 

 tionably to this somewhat variable species. 



13. Cecum regulare, Carp. 



St. 122. Sept. 10, 1873. Lat. 9° 5' S., long. 34° 50' W. Off 

 Pernambuco. 350 fms. Mud. One specimen. 



This specimen differs a little from Carpenter's description of O. 

 regulare, but not enough to justify its erection into a separate species. 





7.'2i 14. Cecum exile, n. sp. 



St. 172. July 22, 1874. Lat. 20° 58' S., long. 175° 9' W. 

 Tongatabu. 18 fms. Coral. One specimen. 



Testa minima, paululo subconica, arcuata, vitrea, diaphana, tenuis, 

 nitida, primum annulata, dein transversim striata, annulis 

 minimis vix expressis, aperturam versus paululo infiata. Aper- 

 tura parum contracta, vix obliqua, marginata, septo vix 

 elevato, submamillato, apice in medio sito. 

 Length 15 mm. Breadth - 3 mm. 



This pretty little species is somewhat broken at the mouth, but is 

 otherwise perfect. It is slightly conical, crystalline, translucent, 

 glossy and very thin. On the upper part there are rings, which 

 though scarcely expressed are quite distinct under a magnifying 



