Besides the few Arctic Chondropterygians, all of which extend into this district, the small shore Dog-fishes are well represented (_Mustelus_, _Galeus_, _Scyllium_, _Pristiurus_); the ubiquitous Rhina or Monk-fish is common; of Rays, _Raja_ predominates in a variety of species over _Torpedo_ and _Trygon_, which are still scarce. Of Acanthopterygians, _Centridermichthys_, _Icelus_, _Triglops_, and _Aspidophoroides_, do not extend from the north into this district; and _Cottus_, _Anarrhichas_, _Centronotus_, _Stichæus_, the _Discoboli_ disappear within its limits. Nearly all the remainder are genera which are also found in the Mediterranean districts. The following are the principal forms, and known to propagate on these shores: _Labrax_; _Serranus_, _Polyprion_, _Dentex_; _Mullus_; _Cantharus_, _Pagrus_, _Pagellus_; _Sebastes_; _Cottus_, _Trigla_, _Agonus_; _Trachinus_; _Sciæna_ (?); _Zeus_; _Trachurus_, _Capros_; _Callionymus_; _Discoboli_; _Lophius_; _Anarrhichas_, _Centronotus_, _Stich__æus_; _Blenniops_, _Zoarces_ (not in Mediterranean); _Cepola_; _Lepadogaster_. Of the Anacanthini the Gadoids are as numerous as in the Arctic Ocean, most being common to both districts; they are represented by _Gadus_, _Gadiculus_, _Merluccius_, _Phycis_, _Molva_, _Motella_, _Raniceps_, and _Brosmius_; but, whilst the majority show their northern origin by not extending into the Mediterranean, _Ammodytes_ and most _Pleuronectidæ_ prove themselves to be the more southern representatives of this order. In the British district we find _Hippoglossus_, _Hippoglossoides_, _Rhombus_, _Phrynorhombus_, _Pleuronectes_, _Solea_, and only the two first are not met with in the Mediterranean. Labroids are common; with the exception of the North American _Tautoga_, all the other genera are met with. Physostomes are not well represented, viz. by one species of _Osmerus_, one of _Engraulis_, one of _Conger_, and about five of _Clupea_. _Syngnathus_ and _Nerophis_ become more common as we proceed southwards; but the existence of Scleroderms and Plectognaths is indicated by single individuals only, stragglers from their southern home, and unable to establish themselves in a climate ungenial to them. The Gadoids are accompanied by _Myxine_; and _Branchiostoma_ may be found in all suitable localities.