NUDIBRANCHIATA. 569 



margin of the foot is round or square and not produced into tentacular prolongations. In 

 its external characters it closely apjjroaches Speirilla but differs in the jaws, teeth, and 

 reproductive organs. The genus is recorded from the Indian Ocean and several parts of the 

 Pacific, including the West Coast of South America, and from the Atlantic. 



31. Phidiana unilineata (A. and H.) ? 



One small specimen from Fadifolu Atoll, Maldives, 25 /, imperfectly preserved. Length 

 9 mm., breadth 2'5 mm. Colour uniform yellowish-white. Cerata partly lost, but apparently 

 arranged in seven indistinct oblique rows, leaving only a narrow space bare in the middle 

 of the back. Foot rounded in front. Tentacles long: rhinophores much shorter. Jaws long 

 and narrow, with a single row of rather distinct denticles. The radula consisting of about 

 25 teeth, bearing from 5 to 8 lateral denticles, two or three of which are not on the 

 basal portion but on the sides of the cusp itself. The penial hook was small but appeared 

 to be shaped as in Bergh's figures of Ph. selencae. 



This specimen perhaps belongs to A. and H.'s Ph. unilineata (I.e.) in view of the habitat 

 and of the fact that there is nothing in its external or internal characters which conflicts 

 with the identification. Still, the anatomical details given by A. and H. do not afford many 

 specific characters, and all trace of the colour has disappeared in this specimen. It is 

 therefore impossible to be sure of the identification. 



Fam. Janidae Bgh.' 



The Janidae closely resemble the true Aeolids, but are distinguished externally by the 

 cerata extending not only all round the sides and end of the back as usual but also in 

 front of the rhinophores along the anterior mantle margin. This character is accompanied 

 by a con-esponding arrangement of the hepatic ramifications which supply the cerata. Further, 

 in most members of the family the radula is multiseriate ; there is a crest between the 

 rhinophores (except in Proctonotus) and the vent is median and dorsal. The genus repre- 

 sented in the present collection, Madrella, does not possess these peculiarities and serves 

 to connect such forms as Janus and P7-octonotus with the ordinary Aeolids. The radula 

 has only three teeth in a row, and the vent is lateral, not dorsal. In all the known genera 

 the reproductive system is unarmed and there are no cnidocysts. 



Gen. Madrella A. and H. 



32. Madrella ferruginosa A. and H. 



One small and immature specimen obtained off a large Antedon laevissima from 

 S. Nilandu Atoll, Maldives, 30 / Length 6 mm., breadth 4 mm. The animal is oval and 

 flat, of a deep copper colour. Round the dorsal margin is set a not very thick band of 

 cerata and on the central area of the notaeum are a few scattered papillae. Both the 

 mantle edge and the foot are wide, but between them there is a deep groove. The vent 

 is at the posterior and the generative opening at the anterior end of the right side. The 

 form of the rhinophores is unusual : they are not perfoliate, but there is a circle of papillae 



1 A.. a.nA K., Monograph of Brit. Nud. Moll. Id. Notice Keniit. d. Aeolidiaden, i. 1S7S. Id. Report on Challenger Nud. 

 of a Coll. of Nud. Moll, made in India. Bergh, Beitrage z. Trinchese, Aeolididae del porta di Genova, 1881. 



G. II. 73 



