1880.] NATURAL SCIENCES OF PHILADELPHIA. 59 



restricted ; and the other, characterized by a more depressed form and 

 the naked rhachis of the tongue, with the B. depressa, A. et H., as 

 type. Hancock has given some anatomical remarks on the typical 

 form {D. bilamellata, L.) ; but nothing else had been since made 

 known about these animals' until my just cited notice and those of G. 

 O. Sars.2 



The Lamellidorides approach the Acanthodorides, but differ even 

 here, externally, by the coarsely granulated surface of the back and 

 by the larger number of the branchial leaves, which are set in the 

 form of a horseshoe ; the openings of the rhinophor-holes, the tenta- 

 cles as well as the genital opening are also of a different shape. 

 More notable still are the anatomical differences ; the Lamellidorides 

 want the armature of the lip-disk, which is found in the other group ; 

 the armature of the tongue is quite different (1, I — 1 — I, 1), and the 

 buccal crop is connected with the bulbus pharyngeus by a stalk. The 

 penis is quite different from that of the Acanthodorides, and without 

 true armature ; the vagina is short. After all the Lamellidorides are 

 much more allied to the Adalarice. 



The form of the body, as in the Acanthodorides, not very depressed. 

 The back covered all over with semi-globular and short club-formed 

 papillae. The openings of the rhinophor-holes with plain margins and 



1 According to H. & A, Adams (the Gen. of Recent Moll., II, 1858, p. 

 657), Lamellidoris is a synonym of ^^ OncMdoris, Blv.," which name is 

 employed by Adams for a group, whose type should be D. pusilla, A., ec 

 H. (that scarcely belongs to the true Lamellidorides). Cf. also Gray, 

 Guide I, 1857, p. 307. 



The genus Onchidoris of Blainville (Man. de Malac, 1825, p. 489, 

 PI. XLVI, f. 8.), ought to be rejected entirely, as founded very likely only 

 on bad observation ; the genus figures with nearly impossible characters, 

 both in relation to the tentacles ("quatre teutacules comme dans les Dori», 

 outre deux appendices labiaux") and to the anus ("median a la partie 

 inferieure et posterieure du rebord du manteau"). The type of the genus 

 Blainville found in the British Mus. (London), where it seemed to have 

 disappeared, at least it was not to be found in the collection of nudi- 

 branchiates which I looked over in May, 1873 (while, on the coutraiy, I 

 found the long-lost type of the genus Linguella, Blv., in his original glass, 

 and so have re-established the denomination Linguella for the much later 

 (1861) Sancara, Bgh. Cf. my Malacolog. Unters., Heft vi, 1874, p. 248). 

 Later, Mr. Abraham (1. c. p. 235) seems to have found the original speci- 

 men again. 



■^ G. O. Sars, Moll. reg. arct. Norv., 1878, p. 306. Tab. XIII, figs. 5, 6 ; 

 Tab. XIV, fig. 2, 3. 



