PLEUROBRANCH^EA. 225 



? Aplysia minor LANKASTER, Philos. Trans., 1875, p. 13 (embryo- 

 logy). 



Pleurobranchcea meckelii Leve, CANTRAINE, Malac. Med. et 

 Litt., p. 87, pi. 3, f. 3. VAYSSIERE, Rech. Moll. Opistobr., Tecti- 

 branches, p. 130, pi. 5, f. 122-125. 



Pleurobranchidium delle chiaii VERANY, Catal. Anim. Invert. 

 Mar. del Golfo di Genova e Nizza, pp. 16, 19 (1846). 



The mouth parts are always protruded in dead specimens. The 

 species is very distinct from other Pleurobranchidce of the Mediter- 

 ranean. 



In establishing the genus Pleurobranchcea, Leue gave no name to 

 the species ; a fact which has been overlooked, probably on account 

 of the rarity of the original paper. De Blainville was the first to 

 use to use the specific name meckelii, which he ascribes to Meckel. 

 It was never published by that author, however, Blainville's refer- 

 ence in Man. de Malac. being a false one ; and while it is possible 

 that Meckel transmitted the specimens to Blainville under that 

 name, no proof thereof is forthcoming, and propriety forbids the 

 citation of Meckel as authority. 



Lankaster, with the embryologist's disdain for exactness in small 

 matters of species and genera, calls it Aplysia minor ! 



P. TARDA Verrill. PI. 53, fig. 86. 



Body subovate, stout, thick, often nearly half as broad as long 

 usually less, tapering backward and blunt posteriorly ; front broad, 

 convex or subtruncate ; back more or less convex or swollen in the 

 middle, with the surface wrinkled or irregularly reticulated, with 

 the sunken lines brown, the reticulations smaller posteriorly. Dorsal 

 tentacles short, stout, wide apart, ear-like, subtubular, having a slit 

 on the outer side, with the edges often rolled in. Gill rather large, 

 well exposed in a dorsal view, situated on the right side, behind the 

 middle, and equal in length to nearly one-fourth the body, plumose 

 bipinnate, with 15 or 16 pinnae on the upper side. Foot broad, often 

 nearly as wide as the mantle, subtruncate or rounded in front, nar- 

 rowed and obtuse posteriorly, ordinarily not extending beyond the 

 mantle. The mantle edge is but little prominent, except along the 

 right side. Proboscis protruded in most of the specimens, large, 

 thick, obtusely tapered close to the end, which is emarginate, show- 

 ing the large odontophore in a broad vertical notch. Reproductive 

 organs large and prominent ; the two orifices are situated on a large 

 tubercle in front of the gill. The male organ, in extension, is long, 

 15 



