288 THE VOYAGE OF H.M.S. CHALLENGER. 



tibus circiter 36, plus miuusvc spinulis brcvibus subacutis cavis ornatis, iustructa. 

 Interstitia costis angustiora, medioeriter profunda, transversim rugose striata. Area 

 dorsalis profunde cxcavata, cuneiformis, fossa ligameutali triangulari sculpta. Pagina 

 interna nitida, hand profunde radiatim sulcata. 



Length 36 mm., height 42, diameter 15.3. 



Habitat. — Station 109, off St. Paul's Rocks in the Atlantic, north-east of Brazil, in 

 104 fathoms ; and Station 201, off the west side of Mindanao, Philippine Islands, in 

 82 fathoms. 



This fine species is very like Lima squamosa, but is l)roader and has more numerous, 

 finer, and more sharpl}^ spined ribs. The anterior straight slope is shorter, the peculiar, 

 triangular ligament-pit is quite different, and the angle formed at the umbones by the 

 dorsal and anterior margins is less acute. 



In reckoning the number of ribs as thirty-six, it should be observed that the very fine 

 ones on the front excavation are not included. The anterior auricles are almost obsolete, 

 and indeed invisible when the valves are regarded sideways, being hidden within the 

 concavity. The hollow spines on the costse are rather pointed, long, and a little curved. 

 The interior of the valves is glossy, and, with the exception of the upper portion, which 

 is thickened witli a shelly deposit, is shallowly grooved and ridged, the grooves corre- 

 sponding to the external ribs. 



The few specimens from the Philippines are all of small size, the largest being only a 

 third the length of the unique shell from the Atlantic. After a very careful study of 

 them I cannot discover any grounds for their separation, the form being the same, the 

 ligament of a similar shape, and the costse only two or three fewer. It therefore appears 

 that this species, like Lima squamosa, occurs in very remote localities. 



Lima multicostata, Sowerby ( = Lima carihtea, d'Orbigny), has about the same number 

 of ribs as this species, but is of' the same form as Lima squamosa. 



The differences which distinguish these three forms are but very slight, and it is not 

 improbable that all belong to one and the same species, and it is curious to note that 

 each of them occurs both in the Atlantic and Pacific. Other closely allied species are 

 Lima tetrica, Gould, from the Gulf of California, Lima huUifera, Deshayes, from 

 Reunion, and Lima zealandica, Sowerby, from New Zealand. 



Lima multicostata, Sowerby. 



Lima multicostata, Sowerby, Thes. Conch., vol. i. p. 85, pi xxii. fig. 38. 

 Lima multicostata, Sowerby, Conch. Icon., vol xviii. pi. i. fig. 4. 



Lima carihcm, d'Orbigny, Sagra's Hist. Cuba, MoHusques, vol. ii. [i. 3.37 ; Atlas, pi. xxviii. 

 figs. 17-19. 



Habitat. — Port Jackson, New South Wales, in 2 to 18 fathoms ; and Station 172, oft' 

 Tongatabu, in 18 fathoms; also Station 56, off Bermuda, in 1075 fathouLS. 



