NOTES ON NUDIBRANCHIATE MOLLUSCS 



229 



The latter have a tendency to develop into epipodial flaps 

 like those of Ancula, and at the same time there appears 

 a tendency to have the normal trace of an epipodial ridge 

 very marked (see Herdman, 

 "Fauna of Liverpool Bay," 

 Report III. p. 133). 



The extent to which these 

 variations may occur can be 

 seen in the following descrip- 

 tion of a specimen dredged 

 in about 20 fathoms near the 

 Farland Pt. during Oct. 1906 

 (see fig.) : 



Length 18 mm., a rather 

 pale - coloured specimen. 

 Velar processes 3 on right side, 

 followed by a very small one 

 which was hardly more than 

 a tubercle, then 2 long ones, 

 i short one and 5 long ones 

 and a tubercle on the left ; 

 i.e. 10 well-developed, slightly 

 contractile, yellow-tipped pro- 

 cesses of normal size, and 

 3 uncoloured small ones (see 

 Garstang, "Journal M.B.A.," 

 vol. i. new series, p. 455). 

 Rhinophores short and thick 

 with a few closely set laminae, 

 yellow tipped. Branchice 7 

 small, tipped with yellow 

 among which was a little 

 black pigment. Cerata large, 

 palmate, consisting of 5 or 6 

 yellow-tipped lobes. Coloured 

 tubercles absent, except the 

 median dorsal row posterior 

 to the branchiae. Eyes very 

 indistinct ; the left anterior 

 angle of the foot coloured 

 yellow, the right being white. 



This specimen, which was healthy and active, lived and 

 spawned in captivity for nearly two months ; the spawn was 

 destroyed by Infusorians. 



Two days later we dredged three more specimens of P. 

 quadrillneata in the same locality. The first was quite a normal 



P. QUADRILINEATA, SHOWING VARIA- 

 TION IN THE CERATA AND VELAR 

 PROCESSES. 



