REPORT ON THE LAMELLIBRANCHIATA. 301 



between tlie two first, wliieli are fuuiul on opposite sides of Africa, than between the first 

 and last, inhabitants of different parts of the same ocean. 



Pecten amicus, n. s^j. (PI. XXI. fig. G). 



Testa compressa, aurantiaco-rufescens, umbones versus albida, costis octo latis 

 rotundatis, liris pluribus tenuibus squamuhitis ornatis, instructa ; interstitia profunda, 

 angusta, minute et pulcherrime reticulata. Auricula postica valv^e dextr« minima, antiea 

 mediocriter magna, inferne baud profunde siuuata, antice oblique curvata, liris radiantibus 

 tenuibus circiter sex, incrementique lineis sculpta. 



Only a single valve of this species, and that evidently immature, is at present known. 

 The sculpture being so remarkable, I do not hesitate to describe it as new. 



It is narrow, compressed, slightly unequal sided, the posterior slope being a little 

 longer than the anterior, and like it nearly rectilinear, together forming an apical angle of 

 about seventy degrees. It is of an orange-reddish tint, gradually paler towards the 

 umbones, and has eight broad rounded ribs which are moderately elevated, " and orna- 

 mented with several very slender prickly-scaled liri^. The grooves between the ribs are 

 narrow, deepish, and ornamented with an excessively fine regular square-meshed network. 

 The auricles are very unequal, the posterior being very small indeed, whilst the anterior 

 (in the right valve) is fairly large, obliquely curved in front, not deeply sinuate beneath, 

 and bears about six fine radiating liroe, which are crossed by the lines of increase. The 

 interior exhibits more or less of the external tinting, which, however, in a more mature 

 shell, would probably be less vivid. 

 ' Length 12 mm., height 14^, probable diameter of the perfect specimen 4. 



Habitat. — Station 172, off Nukalofa, Tongatabu, in 18 fathoms. 



Pecten tigris and Pecten jxs-felis are rather like this species in general appearance, 

 but differ in the detail of the sculpture, both of them being finely Urate in the sulci 

 between the ridges and sculptured with a difterent mici'oscojiic ornamentation. 



Pecten testes, Bivona. 



Pecten tedm, Bivona, Philippi, Enum. Moll. Sicil., vol. i. p. 81, pi. v. fig. 17, vol. ii. p. 57. 

 Pecten sfriatus, var. fartivus, Forbes and Ilauley, Brit. Moll., vol. iv. pi. li. tig. 2. 



Habitat. — Station 75, off Fayal, Azores, in 450 fathoms ; volcanic mud. 



Only a single valve was obtained of this species, which has not, I believe, been recorded 

 from so southern a locality. It exactly agrees with ]\Iediterranean specimens with which 

 I have compared it, being quite smooth, with th(.' exception of flic microscopic decussation 

 as described hy Philippi. 



