388 Mr. Gwyn Jeffreys on Dredging among the Hebrides. 



second is Zetlandic, Scandinavian, and North American, although 

 it has also been procured in the Orkneys and on the Aberdeen- 

 shire coast; the third is Zetlandic, and the fourth Zetlandic also 

 and Norwegian. It must be borne in mind, as regards the 

 extent of geographical distribution, that the southern extremity 

 of the Shetland Isles is distant about 200 miles from the north- 

 ern extremity of the Hebrides "as the fish swims.'' Besides 

 the four last-named species, the following seem to reach their 

 most southern limit in the Hebrides : — Lima elliptica, Leda 

 pygmcea, and Trochus Groenlandicus. Leda pygmaa has indeed 

 been dredged on the coast of Antrim ; but I am now inclined to 

 regard the specimens thus obtained as quaternary fossils. 

 Tethea cranium (a sponge not before known south of Shetland) 

 occurred in tolerable numbers on the Ross-shire side of the 

 Minch. Species of Mollusca, inhabiting the Hebridean seas, 

 which are in the main northern (although they have been found 

 somewhat further south, and some of them occasionally even in 

 the Mediterranean), are — Argiope cistellula, Pecten striatus, 

 Mytilus phaseolinus, Modiolaria nigra, Crenella decussata^ Nucula 

 tenuis, Leda minuta, Area pectunculoides, Montacuta ferruginosa, 

 Cyamium minutum, Cardium minimum, Cyprina Islandica, Astarte 

 compressa, Tellina pusilla, Scrobicularia nitida, Thracia convexa, 

 My a arenaria, M. truncata, Chiton Hanleyi, C. albus, C. ruber, 

 C. marmoreus, Tectura testudinalis, T.fulva, Propilidium ancyloides, 

 Puncturella Noachina, Emarginula crassa, Scissurella crispata, 

 Trochus helicinus, Lacuna divaricata, L. puteolus, L. pallidula, 

 Rissoa albella, Jeffrey sia diaphana, J. opalina, Odostomia minima, 

 0. albella, 0. insculpta, 0. diaphana, Velutina plicatilis, V. 

 lavigata, Trichotropis borealis, Purpura lapillus, Buccinum unda- 

 tum, Trophon Barvicensis, T. truncatus or Banffius, Fusus anti- 

 quus, F. gracilis, Nassa incrassata, Mangelia turricula, Defrancia 

 scabra, Cylichna nitidula, Amphisphyra hyalina, Philine scabra, 

 P. pruinosa, and P. quadrata. 



For certain species, which are almost peculiar to the Hebrides, 

 I am not aware that any locality has been recorded between that 

 district and the Mediterranean. Such are Axinus ferruginosus, 

 Poromya granulata, Neeera abbreviata, N. costellata, and Cylichna 

 acuminata. The first three of these were described by the late 

 Professor Edward Forbes, in the Report to the Association in 

 1843 on ^gean Invertebrata. Another Hebridean species 

 {Nucula sulcata) is not found southwards nearer than the coast 

 of Spain. 



Some of our most conspicuous and prized shells, that are also 

 of a northern type, are wanting in the Hebrides. Saxicava 

 Norvegica, Natica Groenlandica, Buccinum Humphrey sianum, 

 Buccinopsis Dalei, Fusus Norvegicus, F. Turtoni, and F. Berni- 



