PLEUROBRANCH AA. 223 
Jaws tessellated as usual, the component plates short, with about 
_ T subequal denticles (figs. 93, 94). Radula with 37 rows of teeth, 
68 to 70 lateral teeth in each half row; teeth long and slightly 
curved, with a shorter cusp accessory to the main one (figs. 90, 91, 
92). This accessory cusp is lacking on the outermost teeth. 
No shell. 
Western Atlantic (Hirondelle), 
Pleurobranchillus morosus BERGH, in Résultats des Campagnes 
Sci. Albert I, fase. iv, p. 28, pl. 4, f 80-93. 
K. srockut Bergh. Amboyna. 
This species of Pleurobranchillus is mentioned but not described 
in Bergh’s paper cited above, p. 28. 
Genus PLEUROBRANCH /A Leue, 1813. 
Pleurobranchea Lrux, de Pleurobranchzea novo Molluscorum 
Genere, Diss. Inaug., ete., Halle, 1813, title-page, and pp. 1-13, 
plate. (Conf., p.11 “cum animal nostrum * * * Pleure- 
branchee vel Pleurobranchidii nomine insigniendum videtur.’’).— 
Pleurobranchea or Pleurobranchidium of Blainville and subsequent 
authors.— Cyanogaster RuDOLPHI (where ?), see Blainville, Man. de 
Malac., p. 471.—Pleurobranchena Meckel, Swainson, Malacol., 
p. 361. 
Body oblong, the united mantle and veil smaller than the foot. 
Serrate in front and produced at the lateral angles, its edge slightly 
overhanging on the right side, but not on the left, posteriorly, or in 
front. Rhinophores inserted far apart, apparently on the mantle. 
Genital apertures as in Pleurobranchus. Mouth proboscidiform. 
Foot with a gland (more or less visible) on posterior part of sole, 
and a spur or horn on the tail. Shell wanting. 
Radula without rachidian teeth, the laterals slender, with a single 
long accessory denticle on the main cusp (pl. 53, fig. 84, P. meckelii 
Blv.). 
The union of mantle and veil, widely separated rhinophores, 
enormous size of the proboscis in dead specimens, and the lack of 
overhanging eaves to the mantle except on the right side, render 
this group very distinct from other Plewrobranchide in appearauce. 
There is a posterior siphon, like that of Aplysiide formed by folding 
of the mantle over the rear end of the gill. 
The species are few and widely scattered. 
