PLEURONECTID^. 
607 
Some of these characters cannot be observed in the fossils, which 
are thus only provisionally determined. The existing species 
inhabit the North Atlantic and Mediterranean. 
Rhombus minimus, Agassiz. 
1796. Pleuronectes quadratulus, Gr. S. Volta, Ittiolit. Veronese, p. cclx. 
pL Ixiii. hg. 3 {errore). 
1835. Rhombus minimus.^ L. Agassiz, Neues Jahrb. p. 301 (name only). 
1839-42. Rhombus minimus, L. Agassiz, Poiss. Foss. vol. iv. p. 289, 
pi. xxxiv. fig. 1. 
1859. Rhombus minimus, A. B. Massalongo, Specimen Photogr. Anim. 
Foss. Agr. Veron. (1859), p. 36, pi. xiii. fig. 1. 
Type. Nearly complete fish ; Palseontological Museum, Munich. 
A very small species, attaining a length of about 0*1. Length 
of head with opercular apparatus contained two and a half times 
in the length from the pectoral arch to the base of the caudal fin ; 
maximum depth of trunk about four fifths of latter measure. 
Vertebrae 11 or 12 in the abdominal, 20 in the caudal region. 
Dorsal and anal fins deepest in their middle portion, the former 
with about 65, the latter with about 45 rays; both these fins 
terminating very close to the caudal, which comprises 17 rays. 
Small scales well developed, apparently cycloid. 
Form. Log. Upper Eocene : N. Italy. 
1657. Fine specimen, 0*06 in length, in counterpart ; Monte 
Bolca. The head is imperfect, but the trunk and median 
fins are well displayed. Appearances suggest a dense 
squamation of small cycloid scales. 
Presented by Chambers Hall, Esq. 
P. 3971. Another good specimen broken and distorted in the 
caudal region; Monte Bolca. The dorsal fin is shown 
arising on the snout. The head and opercular apparatus 
are tolerably well preserved ; and the delicate pectoral fin 
is seen. Some of the abdominal vertebrae exhibit their 
large transverse processes ; and there are remains of the 
small, slender ribs. EnnisTcillen Coll. 
Dermal tubercles resembling those of the existing Rhombus 
maximus, Cuv., are recorded from the Lower Pliocene of Orciano, 
Tuscany, under the name of Rhombus gentiluomoi by B. Lawley, 
Nuovi Studi Pesci, etc., CoUine Toscane (1876), p. 82.^ 
The following small extinct species have also been referred 
to this genus, but are not represented in the Collection :— 
