1. i'iJKo.M\;iu.\. -^"'^ 



p. 41, taf. 78. fig-. 1 ; HI. Schu. p. .":;0; Dunuv. Brit. Fish. pi. ^0 ; 



l\iU. Zoof/i: i?<«s\-.'l.s. iii. p. (iO ; Ekdiom, Fiache Morhi>,]).'-2y>7 ; 



Flon. Jir'it. An. p ■104 ; Jctn/i)^, Man. p. nLM ; Varn. Fish. Firth of 



Forth, p. 284; YarrcU, Brit. Fish. 2iid o.'it. ii. p. .■)98, or, \)\x\ 



edit. i. p. 28*; Xil.is. Skaiul. Fiiini. Fish. p. 74/> ; llirhards. Faun. 



Bor.-Amcr Fi.th. p. 25>4 ; i^c/i/s-LoJii/chaiiips, Faviic BrhjCj p. 22G ; 



Krdi/cr, Dajiiii. Fish. iii. p. 1042 ; O'ihith. Fisch. JVichar's, ]i. 134 ; 



Trcc'hcl L^ Kncr, Siisswassnf. p. o77, lig. 202 ; Aiu/. Midler, in 



Miii/cr's Arch. 18-"jG, p. ;32'>; ,Sifbuld, ,'ilissH-asscrf. p. .■J72 ; Grotiyv. 



Si/st. ed. ^/>w/, p. I ; B/tiHchard, I'oiss. France, p. olo: Canestrini, 



Arch. p. hi Zool. iv. p. 185. 

 Lamperu, Vcnti. Brit. Zool. iii. p. lO('), pi. 10; Couch, Fi:M. Brit. Isl. 



iv. p. ;J05, pi. 247. ti-!-. 2. 

 Petroniyzoii aro-enteiis, Bl. taf. 415. iio-. 2 ; Bl. Schn. p. 532, tab. 102. 



fig. 1 ; Couch, I. c. p. 400, pi. 247. fig. 3. 



piicka, Laccp. i. p. 18. 



juivie, MacCulIoch, West. Isles, ii. p. 180, pi. 29. 



nigncaus, Lesucur, Trans. Am. Phil. Soc. i. p. 385; Storrr, Mem. 



Amer. Ac. ix. 18(37, p. 253, pi. 3!,l. fig. (5. 

 Lainpetra fiiiviatilis, Grau, Chondropt. p. 140, orP/wc. Zoul. Soc. 1851. 



p. 237, pi. 4. fig. 2. 

 Petroinvzoii onialii, Van Bencdoi, Bull. Ac. Sc. Belt/, i'l. 1857, p. 540, 



figs. 1-3, aud XX. 1805, p. 40 ; Muhn, Forhandl! .b7c<//((/. vtrf. Sd- 



mode. Kjobonb. 1800, p. 580. 

 Organ of bearing: Ow-j/annihoio, Mem. Ac. Sc. St. ritersh. viii. 1804. 



Maxillary tooth single, forming a transverse ridge with a cusp at 

 each end ; mandibnlary t-ootli single, crcsccnt-sli;ii)ed, ■with about 

 seven cusps. Tongue with a broad, transverse, trenchant tooth, Avhich 

 is provided with a median cusp. Two or tliree bi- or tricuspid teeth 

 ou each side of the gullet ; the other teeth of the suctorial dislc are 

 small and not numerous. First dorsal fin separated from the second 

 by an interspace. Coloration immaculate ; sides silvery. 



Coasts and nvers of Europe, North America, and Japan. 



a, b, c-d, e~f. Adult and half-grown. England. 



ff, h, i, h-l. Adult. Holland. 



in-q. Adult. Eelgium. Presented by Prof, van Leneden as 1\ 



omalii. 

 r. Ten inches long. North America. Purchased of Isl. Parzudaki. 

 s. Nine inches long. Russian North America. From Hr. G ruber's 



Collection. 

 I am indebted to Prof, van Peneden for the opportunity of com- 

 paring specimens of his P. o»mZu with examples oi J'.Jhiriatilis from 

 Holland, England, and other countries, and have come to the conclu- 

 sion that there is no specific diff'erence between them. This may ap- 

 pear a matter of surprise to those who, without specimens, consult 

 the description and figure given by Prof, van lieneden. He repre- 

 sents the new species as finless, but in the examples sent the fins are 

 well developed, and of exactly tlie same shape and position as in J'. 

 Jlnviatilis With regard to the dentition, J', omalii is represented 

 with ten ])oiiits to the mandibular lamina, and without small teeth 



* Fipurr of dcnt'ti'm iiirorrcct 



