70 " ENDEAVOUR " SCIENTIFIC RESULTS. 



contracted at the base then produced to the canal. Apex 

 mucronate, of two smooth whorls. Epidermis thin, membranous 

 and easily shredded. Sculpture : low broad radial ribs ascend 

 the spire obliquely at the rate of about a dozen to a whorl, but 

 vanish on the last. There are eight spiral cords, the four 

 lower are wider spaced than those above, of which two ascend 

 the spire. Each cord carries distant high vaulted scales, some- 

 times projecting as long spines, those on the shoulder and the 

 base being most developed, set at the rate of twelve or fifteen to 

 a whorl. Besides, there is an unarmed spiral beneath the 

 suture and another margining the umbilicus. Perforation broad 

 and deep, expanding finally and penetrating as a spiral tube to 

 the earlier whorls, its surface is spirally grooved and transver- 

 sely scaled. Aperture elliptical, outer lip fimbriated by incipient 

 scales, inner lip spread above on the preceding whorl for a 

 short space, then projecting free for the rest of its course. 

 Above, the aperture is slightly channeled, below it passes into a 

 short narrow and recurved canal. Deep within the aperture, 

 and low on the columella, appear three strong well spaced plaits, 

 of which the lowest nearly overlies the umbilical margin of the 

 former whorl. Length, 130 ; breadth, 65 mm. 



Hal. Four empty shells were trawled in from 80 to 120 

 fathoms in the Great Australian Bight, between Long. 126 and 

 129 E., Feb. April, 1913. A few specimens of coral, 

 apparently a Cylicia, are attached to one, and on another are 

 Polyzoa, which suggest that the mollusc lived on hard ground. 



2. From NORTH AND SOUTH OF GABO ISLAND. 

 Genus FORAMELTNA, yen. nov. 



A genus related to Mdinu, in Avhich the byssus instead of 

 escaping by a lateral notch, penetrates the right valve by a 

 median subumbonal orifice and groove. A suture extends from 

 the perforation posteriorly to the edge of the hinge. Adductor 

 muscle single, concentrated and reduced. Ligamental furrows 

 narrow and crowded. Type : F. exempla. 



An affinity with Anomia is suggested by the perforation, but 

 convergence has probably here as with Perl-inn reached similar 

 results from unlike origins. The multivincular ligament and 

 general appearance of the shell indicate rather that this is a deriva- 

 tive from the stock of Melhia. In typical species of that genus the 

 byssal notch forms a pouch and if the byssus had pressed more 

 on one valve than on the other, further advance might have 

 enclosed the byssus in a tube. With a transition form, 

 M. percrassa, Tate, 1 an approach seems to be made to such a 



1 Tate Traus. Eoy. 800. S. Anstr., xxxiii., 1899, p. 277. 



