NUDIBRANCHIATA. 567 



short and broad, 9'5 mm. long, 6 mm. broad across the back : foot 3 mm. broad. The colour 

 of the dorsal surface and of the tentacular shield is blackish. Down the middle of the 

 back runs one fairly straight line. On each side of it are eleven or twelve other lines, 

 not parallel to it, but arising with it at a point behind the rhinophores and going off 

 towards the mantle edge at various angles in a posterior direction. All these lines as well 

 as the borders of the mantle of the tentacular shield are raised, very distinct, and of a 

 whitish-yellow, which contrasts strongly with the ground colour. Numerous cnidopores were 

 distinctly visible on the mantle edge. The anterior corners of the foot are produced. The 

 anterior mantle edge is continuous, but deeply notched above the rhinophores. 



The jaws are as usual in the genus, with several (at least six) rows of denticles on 

 the cutting edge. The radula of about 20 fully developed rows. The rhachidian tooth of 

 the usual shape with a long central cusp and about 6 denticles on each side. The first 

 lateral squarish, with about 5 denticles on the outer side. The other laterals were 9 — 11 

 in number in the various rows and, as far as I could see, not denticulate. The inner are 

 broad and somewhat clumsily shaped hooks: the outer narrower and of the ordinary hamate 

 type. The intestines were much hardened and little could be made out of them, but the 

 ramifications of the liver seemed discernible. 



Van Hasselt's description of his D. striatus is as follows^ " Corpore nigi'o, flavo fuscoque 

 variegatissimo : dorso mucoso sulcato, sulcis simplicibus longitudinalibus, rectis parallelis : 

 capitis et pedis margine flavo: tentaculis apice nigris: pallio antice emarginato. Long, pallii 

 O'Oll : lat. 0003. Corporis totius 0"1. Hab. Anjer-baie (Sunda Strait) vulgaris." This 

 description seems applicable to the present animal except that the doreal stripes are not 

 strictly speaking straight and parallel. A comparison of several specimens might show some 

 variation in this respect, and as van Hasselt says the animal is common they may be 

 found in the future. Meanwhile, I see no reason why this animal should not bear the 

 name striata. 



Fam. Dotonidae-. 



The Dotonidae are closely allied to the Aeolididae in both external and internal structure. 

 The rhinophores however are simple and retractile into wide cup-shaped sheaths. The cerata 

 are arranged in two rows and as a rule are large, ovate, and at least some of them 

 compound. They contain ample and many lobed hepatic ramifications. As a rule there are 

 no anterior tentacles, but a rounded frontal veil. The vent is latero-dorsal. Cnidocysts are 

 absent. The jaws are weak and not denticulate. The radula uniseriate (as a rule): the 

 teeth with a central cusp and more or less distinct lateral denticles. The reproductive 

 system is unarmed. 



The Dotonidae as a family are distinguished from the Aeolididae by one character 

 only — the rhinophore sheaths. The genus Doto is also marked by its ovate compound cerata 

 and its frontal veil, but a formation of the head analogous to the latter is also found in 

 Embletonia, and the nodules on the cerata of Capellinia and Proctoiwtus seem a step in 

 the direction of the composite condition. The other genera of the family are less well known 

 and differ from Boto chiefly in having some or all of the cerata simple and not compound. 



' I quote from Bergh's quotation S. R. vi. p. 277, not Porto di Genova, 1881. Vayssi&re, Recherches stir les Mol- 

 having access here (East Africa) to the original work. lasques Opisthobranches de Marseilles, 1888. Bergh, Beitr. 



~ A. and H., Brit. Nud. Moll. Trinchese, Aeolididae del z. Kenntniss der AeoUdiaden, vi. Id. S. R. xvi. 



