148 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY. 



DofilOPSILLA PeLSENEEEI (?), AKEOLATA (?). 



(See Oliveira, " Opisthobranches de Portugal," Coimbra, 1895, p. 12; 

 Bergh, Jabrbiich. deutsch. malak. Gesell., 1880, vol. vii, p. 316; 

 id., Zool. Jabrb;Syst., vol. ix (1896), p. 454; Vayssiere, Exped. 

 scieiit. " Travailleur " et "Talisman," 1902, p. 235; id., Ann. 

 Mus. Marseille, 1901, vol. vi, p. 50, pi. vii, figs. 8-10.) 



Mr. Cros&land's notes on tbe living animal are as follows : — 



" From a tidal pool, well above the low tide level. The slug 

 exposes itself to the sun. Very flat in shape, with ample mantle. 

 Rather rough and stiff to the touch, but not^ remarkably so. Back 

 warty. Gills 3, tripiuuate. They often appear to be rather small, 

 but can be expanded to a very ample size. Edges of the gill and 

 rhinophore-pocket distinctly raised, especially the latter. 



" In crawling, the foot just visible behind the mantle. 



"Colour brilliant yellow, but the four specimens vary in the depth 

 of their colour, according to their size. The smallest has a mere 

 tinge of light yellow, but the gills, and especially the rhinophores, 

 are distinctly yelluw. The largest is a very deep yellow, and the 

 rhinophores are almost brown. Some of the warts are sand-coloured. 

 Under side rather lighter in colour. Foot very broad. The heart can 

 be seen pulsating, and the gills move in time with it. In the largest 

 specimen there are five gills. Mantle-margin wavy." 



The largest of the preserved specimens is about 20 mm. long, 

 12 mm. broad, and 5 high. The external characters are as described. 

 The back is covered with tubercles, but they are flatter and less 

 noticeable in the centre. This, however, may be due to accidental 

 external pressure. The mantle-edge is ample and thin, with an 

 internal reticulate pattern, which can be seen from the under side. 

 It is formed of spicules arranged in bundles, which anastomose, and 

 are so distinct that they actually project as ridges. Many of the 

 spicules have a prominence on one side, and are sometimes almost 

 Y-shaped. The whole arrangement resembles that found in the 

 Californian Doridopsis reticulata. The foot is broad, with expanded 

 margins ; it is rounded before and behind, but no anterior groove is 

 visible. The branchiae are five in the largest specimen. Two small 

 and indistinct lobes above the mouth seem to represent the oral 

 tentacles. 



The digestive tract is much as described by Vayssiere for B. areolata. 

 The tube which issues from the buccal cone is bent on itself and 

 describes a complete circle ; it then passes through the nerve collar, 

 runs backwards, and, after becoming very thin and constricted for 

 a short space, dilates into a small round pouch. It is ringed or 

 striated transversely for its whole length. The round pouch is 

 succeeded by another constriction and a sausage-like dilatation. 



The gians penis is armed with hooks. They have rather broad 

 bases, and are of irregular and sometimes rather wavy outline. 



The central nervous system is enclosed in a hard capsule. The 

 ganglia are more distinct than is usual in the Doridopsidse, but lie 

 close together so that the commissures are short or absent. The eyes 



