1881.] THE SURVEY OF H. M.S. 'alert.' 41 



Gould, and agrees exactly with the single shell above described. In 

 assigning P. tvardiana to Carpenter, and California as its locality, 

 Sowerby has exhibited a great want of care. 



LoRiPES PERTENUis, sp. n. (Plate V. fig. 5.) 



Shell very thin, compressed, obliquely subcircular, white, inequi- 

 lateral. Valves concentrically finely striated, vvith a shallow groove 

 running from the umbo down to the jiosterior end, but at a very 

 little distance from the dorsal margin, and with a second depression 

 bordering the dorsal edge. Umbones acute, rather prominent, 

 situated very much forward. Hinge absolutely toothless. Interior 

 of valves exhibiting traces of iridescence. Width 10 raillims., 

 length 9, thickness 4g. 



Hab. Straits of Magellan. 



This species is remarkable for its extreme fragility and the shallow 

 depressions down the posterior dorsal slope. 



Kellia magellanica, sp. n. (Plate V. figs. G-6 b.) 



Shell equivalve, subequilateral, white, covered with a yellowish- 

 olive epidermis, for the most part worn off, of an ovate form, a trifle 

 narrowing anteriorly, the outline being interrupted by the pro- 

 minence of the umbones, rather ventricose. Sculpture consisting 

 of rather coarse concentric lines of growth. Umbones rather acute 

 and prominent, somewhat curved anteriorly. Interior of valves of 

 a bluish white, except at the margin, where the epidermis is narrowly 

 reflexed within. Hinge composed of two stout teeth in the right 

 valve — one immediately beneath the umbo, and the second rather 

 widely separated from it by the intervening cartilage. Also two 

 teeth beneath the apex in the left valve, and a third corresponding 

 to the second tooth in the other valve, also parted off from the others 

 by the internal ligament. Scars and pallial line indistinct ; the 

 latter appears quite simple. Width 8| millims., length 7-k> thick- 

 ness 5. 



Hab. Station 6. 



This species is very much like the British K. suborbicularis, yet 

 on close investigation appears distinct. It is more solid, has a 

 stouter epidermis, stronger teeth, and the form is not quite the same. 

 K, bidlata, Phihppi, also a Magellan species, must be very nearly 

 allied to the present ; yet the form, as described in the ' Archiv f iir 

 Naturgeschichte,' appears to differ. K. magellanica is almost equi- 

 lateral, whilst K. bullata is said to be " voru weit liinger als hinteu." 



ASTARTE MAGELLANICA, Sp. U, (Plate V. fig. 7.) 



Shell small, subequilateral, elevated, subpyriform, and not very 

 tumid, concentrically sulcated ; beaks prominent, acute, curving 

 considerably anteriorly. Lunule indistinct. The dorsal slope on 

 that side rather incurved, posterior one regularly curved, basal 

 margin broadly arcuate. Concentric waves numerous, close-set, 

 very fine upon the umbones, gradually increasing in stoutness, 

 attenuating at the sides. Epidermis thin, greenish yellow. Interior 



