1837.] Notice on Balantium. 151 



that they are hicarinate, instead of presenting a single edge or keel. 

 The other face has only one. broad central elevation, which expands 

 gradually, and in proportion to the increase in width of the shell, 

 towards the superior aperture. My shell is shorter in proportion 

 than B. recurvum. 1 propose to describe it as 

 Balantium Bicarinatum. 

 Testa compre?sa sub-triangulari hastiformi, faciebus utrisque trans- 

 verse sulcatis, superiori triradiata, radiis convexis, approximatis ad 

 rnarginem superiorem provectum undulas tres formantibus ; facie 

 infeiiore medio convexa, abbreviate ; marginibus lateralibus lsevibus 

 unisulcatis, sub-bicarinatis. 

 Long. 0.65, Lat. 0.5 poll. 



Habitat in Oceano Indico Australi, non procul ab insulis Amster- 

 dam et Sancti Pauli dictis. 



1 took the shell on the night of the 28th November, 1834, in S. 

 lat. 36° 30', and E. long. 75° 30', in company with Janthina exigua 

 and another small flat spired species, Cleodora, Hyalcea, a small Cepha- 

 lopode of the genus Cranchia, an independent floating Anatifera, and 

 a crustaceou* marine Centipede. With the exception of a protrusion 

 of a small portion of the Molluscum at the apex, the animal was very 

 similar to that of Cleodora, but having been crowded with too many 

 specimens in spirits of insufficient strength, it decayed, and was no 

 longer recognizable, when I had an opportunity of substituting a 

 stronger preservative liquor. 



I observe that De Ferussac, in his enumeration of the species of 

 Pteropoda, contained in No. 262 of the Bulletin des Sciences, has refer- 

 red B. recurvum to the genus Cleodom, as C. Balantium. As the only 

 habitat given by him is Congo, it is evident that he was possessed of 

 no information in addition to that contained in the Journal of Science, 

 and that he had arbitrarily assumed the specimen to be defective in 

 the apex. The discovery of another species with a similarly perfo- 

 rated extremity, and a like flattened form, should cause us to hesitate 

 before blotting out the genus indicated by the writer in the Journal 

 of the Royal Institution. Nothing but the discovery of an imperfo- 

 rate specimen should now permit its annexation to Cleodora, between 

 which and Hyalcea it appe irs to supply a void. The parts of Pelagian 

 shells which are most subject to injury are the delicate edges of the 

 apertures, not the imperforate apices, which even in the tender spinous 

 terminations of the Cresides and Cleodora, are always met with in a 

 perfect state. Cuoieria forms no exception to the rule, as, in that 

 genus, the spinous termination is cut off by a diaphragm, and the 

 derelict portion, therefore, follows the ordinary rule observable in 



