Illustrations of the recent conchology of Great Britain and Ireland, with the description and localities of all the species, marine, land and fresh water

[SESSILIA, 120 MOLLUSCA. Found on thc Northumbcrlancl coast, ncar Scaton, ,Jardinc's cabinct. In Lady r,. PENTELASMIS nADULA, pi. LI, f. 3, . Anatifa ,·adula, First Ed., pi, 5, f. 3 ; Pcntelasmts mdttla, L I uss . Lepas clentata, Brown, Ency. Brit., VI, P· 404. cae 1, ,u •, • d · ¡ Shell subcompressed ; the larger valves acu~ely pon~te 'w1t i regular series of prominent, oblique ribs, the1r anterior edges with six sharp, saw-likc teeth, the superior ones lar~est, ancl graclually diminishing as thcy desccnd, thickly bcset w1th sha~p, imbricated scales, which have a rasp-like appcarance; superior valves terminating in a lengthened, acule point, and covered by undulating, rough striro ; dorsal valve arcuated, ami smooth ; peduncle very small. Besides the ribs on the larger valves, the series of. t~eth _on thc anterior margins of the \arger valvcs will al once d1stmguish this curious specics from P. clentatus, in which the scrrated tceth are placed on the centre of the dorsal va\ve. Found on the Devoushire coast, but is very rare. 6. PENTELASMIS l'ASCICULAnIA, pi. LI, f. 2. A 11atifa fc1scic11lm·iC1, First Ecl., pi. 5, f. 2; P c11talC1smis Btlisii Lcach, MSS., p. I ; A natifc, vítrea, Lamarck, V, p. 405; Ellis, Zoophytcs, p. 167, pi. 15, f. 6; L e¡msfC1scic11laris, Montagu,· p, 557; Mat on all(I Uackett, p. 30; L epas clilata, Donovan, pi, 14•1. Shell of a palc horn-colour, extremcly thin and fragile; valves with large wrinkles; larger valves much expamled posteriorly, an<I becoming suddenly hollow, terminnte in a beak-like point; clorsnl valve with an acule protuberance in its centre, and fre- qucntly with one bclow ; apicial valves rnuch pointed, ami have a considerable inclination backwards, producing a convcxity on the anterior sidc of thc shcll ; peduncle vcry short, and vcry thin. This specics is always found congregating in largc rnasscs. First found in the British Channel, ami has bccn since met wi th 011 many of thc British coasts, and especially on the west- ern coasl of Ire\ancl. ORDER II.-SESSILIA. GENUS J.-PYRCOM.1,-Sal'igny. Shell univalve, somcwhat conical, genernlly compresscd, and usually scated on l\fadreporcs or othcr zoophytes; open at the apcx, which is small, ali() protccted by a four-ya\vcd operculurn, thc posterior ones sornetimes much elongated, these are varia- ble, ami closcd at the base by a dccply cup-shaped testaceous "nlve; inside perpcndicularly striated or groo,•ed. 1. PrncO)lA ANCLJCA, pi. LIII, f. 27, 28, 29. Ad11" A11glica, First Ed., pi. 7, f. 27, 28, 29; L cach, MSS., P· 1. Shell conical, longitudina\ly ribbcd, with many, ncarly obso- ·1ete, transversc wrinkles; apcx with a Ycry srnall aperture, ami protectcd by a bh•alve, obliquely striatcrl opcrculum; colour rosy. Fig. 28, the operculurn. lnhabits the Coiyopliillia A11glica, in Plymouth Sound. ami 1s frcqucntly found GENUS 2.-BALANUS,-Bruguicrc. Shell sessilc, conical; frequently an clongate<l cone; com- posc<l of six valves, fo~1· of which are larger than the olher~, anrl of ncarly cqual s1ze, and ali of them locked by the1r sides; apex open, of a subtrigonal ~r ~lliptical form; base closcd by a teslaccous plale, by wluch 1t adhcres to extra- neous subslanccs; opcrculum biparlitc, ami consisting of four val ves, of which the posterio1· pair are the rnost. prominent; exterior surface always co1·ered by a thin, clastic, horny epi- dermis. J. BALANUS DALAJ';0IDES, pi. LIII, f. 17, and pi. LIV, f. 4, 5. Balanus ovularis, First Ed., pi. 6, f. 4, 5, and pi. 7, f. 1 í; Lamarck, V, p. 392; BC1la11·us balmioides, Montagu, p. 7; Lepas balanoides, Donovan, pi. 36, f. 2; Maton an<l Hackctt, p. 23; Brown, Ency. Brit., VI, p. 402, Shcll subconic, subdcpresscd; valves srnooth, white, somc- timcs clecply sulcatcd at. the base; apcrturc wide; operculum with the two anterior ,•alvcs slightly striatcd transversely, the posterior ones smooth. Fig. 8, 9, l'ah•es of t.he opcrculum. Fig. 5, an elongated varicty. A very comrnon species, adhering to muscles and oystcrs. 2. BALANUS co~IMUNIS, pi. LIII, f. 23, and pi. LIV, f. l. Balmms commwiis, First Ed., pi. 6, f. 1, ami pi. 7, f. 23; Montagu, p. 6; L epas Balcmus, Pennant, IV, P· 72, pi. 3í, f. 4 ; Donovan, I , pi. 30, f. l ; Maton and Rackett, p. 23 ; Flc- rning, Edin. Ency., Art. Conch., p. 102. Shell strong, rugged, conic, compart rncnts · unequal, with many irregular, longitudinal, squamrnosc ribs; the intcrsticcs with trnns ,·crse wrinkles; aperture rather contrnctcd, and fur- nished with a four -vahcd opercu\urn; posterior valves sprcading a little al thc apcx; anterior valves trans1·crsely striatcd, ancl provided with a longitudinal furrow; colour cinercous-brown. Cornmon on most of the coasts of Brilain ancl Ircland, ad- hering t o cxtraneous substances. 3. 13ALANUS nucosus, pi. LIII, f. 4, 7, 8, ami 21, and pi. LIV, f. 6. Bc,lcmus 1·11gosus, First Ed., pi. 6, f. 6, and pi. 7, f. 4 and 20; Montagu, p. 8; Flcrning, Edin. Ency., Art. Conch., p. 101 ; Maton and Ilackett, p. 25; L epas borealis, Donovnn, pi. 160, lowcr figure. Shell subconic, divided into six compartments by irregular, incquidistant furrows, those of the posterior side broadest, ami crossed with dcep <livisions, formed by the \incs of growth, these are sornelirncs wrinkled or striatcd longitndinally; npcr- ture vcry large, inne1· margin transverscly riclged, and closcd by a four-valvcd operculum; the dorsal rnlvcs n little apart nncl rcílexed at thc apex ; upper half of anterior yah-es smooth, with transYersc, strong striro on thcir lowcr half ; colour crcam- whitc. Fig. 2 1, an elongate<l Yaricty, the JJ.jist11los11s of nuthor;:. Fig. 13, 14, the operculum. Common on many of the British ami Irish consts. -1. BALANUS C0STATUS, pi. LIV, f. 2, 3. Balmms costatus, First Ed., pi. 6, f. 2, 3; Montagu, p, 11 ; Flcming, E<lin. Ency., Art. Conch., P· 101 ; L epas costata, Donornn, 1, pi. 30, f. 2; I\Intou :Jll(I Hackctt, p. 2-1.