224 PLEUROBRANCH@A. 
P. MECKELI Blainville. Pl. 53, figs. 81, 82, 83, 84, 85. 
Body oblong, very convex, pale brownish-gray with numerous 
spots or marbling of blackish-brown over the whole upper surface, 
the sole almost black, the posterior pedal gland whitish gray. In 
alcohol the color fades to a very pale gray, dark spots indistinct, sole 
vermiculate with blackish. Mantle covering only the median part 
of body, not projecting or sharply defined on the left side and be- 
hind, narrowly overhanging on right side; in front produced forward 
in a crescentic head-piece with laterally projecting processes, fore 
margin serrate; folded into a permanent excurrent siphon on the 
right side behind. Rhinophores situated on mantle, wide apart, 
truncate, slit and rolled; gill small, inserted behind middle of 
mantle, mainly adnate, bipinnate. Female genital pore on a papilla 
at anterior insertion of gill; male orifice or penis in front of it. 
Rostrum, in alcoholic specimens, extremely large and protruding 
far in front. Foot oblong, subtruncate in front, tapering and 
rounded behind, having a gland on the sole behind, which excretes 
through a duct opening on a horn-like papilla on the upper surface 
of the tail. Shell none, but a large shell-cavity present. 
Length of alcoholic specimen with protruded rostrum 55, breadth 
21 mill. 
Palermo, Sicily (Phil.) ; Naples (Phil., Cantraine); Gulf of Mar- 
seilles (V ayssiére). 
Pleurobranchea Lrur, De Pleurobranchza novo Molluscorum 
Genere, 1813, pp. 1-12, plate. 
? Pleur. balearicus Laroche, Cuvier, Regne Anim., ii, (1817), p. 
396, footnote (nude name, the identity of which with P. meckelii is 
surmised by de Blainville). 
Pleurobranchidium meckelii Meckel, BLAINVILLE, Dict. Sci. Nat., 
xxxxi, p. 376 (1826) ; Man. de Malaec., p. 471, pl. 43, f. 3 (false 
reference to Meckel’s Beytrage vergleich. Anat.). 
Pleurobranchidium meckelii DELLE Cu1aJE Memorie, ii, p. 159, 
pl. 40, f. 11-17 (1828). 
Pleurobranchea meckelii Lewe, Puttier1, Enum. Moll. Sicil., ii, 
p. 88. 
Pleurobranchea meckelii Leue, DesHAyEs, in Cuvier’s Regne, 
Anim., Moll., p. 89, pl. 32, f. 2, 2a—Brreu, Rés. Camp. Sci. 
Albert I, fase. iv, pl. 4, f. 96-99. 
Pleurobranchidium meckelii Blainy., Desu., Trait. Elém. de Con- 
ehyl., pl. 9ljf 1) 2: 
