MOLLUSCA OF PLYMOUTH SOUND. 179 



3. LamellidoeiSj Alder and Hancock. 



6. L. BiLAMELLATA, Linueiis. 



Thirty or forty specimens were obtained from the mouth of tlie 

 Yealm, October 20th, 1888. Occurs also inside the Sound at Batten 

 and Jennycliff. Seven or eight obtained with the dredge from off 

 the Duke Rock, January 23rd this year. 



7. L. SPARS A, A. and R. 



Two specimens of this rare species were obtained with the dredge 

 in fifteen fathoms water off Stoke Point, January 17th, 1889. Each 

 was just a quarter of an inch in length, ovate in form, and nearly 

 equally rounded at both ends. One was of a brownish-pink colour, 

 deepening just behind the tentacles and within the branchial circle, 

 the other was of the same general hue but very pale and slightly 

 purplish in the middle of the back. A character which was marked 

 in each of these specimens, but which Alder and Hancock have not 

 mentioned in the account of their specimen, is that the spiculose 

 tubercles on the back were each surrounded by a ring of blackish pig- 

 ment, and generally contained a black spot in their centres. Hancock's 

 drawing (Monograph, fig. 3) represents these markings, although 

 there is no mention of them in the text. The tentacles were 

 yellowish white with brown spots or patches ; the tubercles on the 

 margins of the tentacular cavities were white with a black spot in 

 the centre of each ; but the " obtuse point behind, '^ mentioned and 

 figured in Alder and Hancock's Monograph, was not well marked in 

 either of these individuals. These specimens also did not show the 

 " few distant reddish-brown freckles or spots " on the back which 

 were strongly marked in their example, I believe the branchial 

 plumes were ten in number, but they were very small, not expanded, 

 and hard to make out. The two were kept alive for several days, 

 but were very torpid and remaiued constantly on the bottom or sides 

 of the dish, never being seen to float on the surface of the water. 



8. L. ASPERA, A. and H. 



A young individual of this species was dredged between the 

 Mallard and Cobbler Buoys on July 25tli of this year. The contents 

 of the dredge were chiefly large quantities of Polyzoa [Bowerhanhia 

 imbricata, Bugula flabellata and avicularia), and it was apparently 

 from among these that the Nudibranch emerged after being placed 

 for some time in a dish. It was only one tenth of an inch in length. 



