MOLLUSCA OF PLYMOUTH. 441 



Solids fed (cf. Alder and Hancock, Monograph). One of the in- 

 dividuals, more closely examined, was found to be f inch long, and 

 was entirely of an opaque white colour except for the rhinophores, 

 which were deeply pigmented brown over the lower two-thirds of their 

 length. The distal portion was pointed at the tip, and opaque white 

 in colour. The infra-apical bulb never assumed the form of the 

 " button-like expansion " figured by Alder and Hancock ; indeed, 

 there was no trace of it at times. Just below the bulb, at the junc- 

 tion of the white and brown portions, the left rhinophore was curi- 

 ously and abruptly bent forwards, and this condition was persistent. 

 The rhinophores over their pigmented portion were finely perfoliate, 

 the laminas apparently resembling those of Facelina 'punctata. 



The cerata react to stimuli upon the head, as in Galvina tricolor j 

 there is no reaction upon touching the back or the cerata them- 

 selves, or to shadows. 



Opaque white spots were distributed upon the back, as described 

 in the Monograph ; they existed also at the tips, and occasionally 

 over the whole external integument of the cerata. 



This individual spawned on a stone a week after its capture, the 

 spawn being exactly as described by Alder and Hancock. 



Another small specimen, ^ inch in length, was taken with the 

 bottom tow-net in Cawsand Bay on the 7th of July. The infra- 

 apical bulb of the rhinophores was quite absent. 



Suh-family 6. — Facblinin^. 

 24. Facelina, Aid. and Hanc. 

 34. *Facelina coronata, Forbes. 



Two more specimens have been dredged near the Duke Rock ; 

 one on September 23rd, 1889, the other in July, 1890. Another 

 fine specimen, 1^ inches in length, was found among Ohelia geniculata 

 on Laminaria dredged near the end of Batten breakwater (west of 

 the Cobbler Buoy) on October 2nd, 1889 : on the same piece of weed 

 were two Galvina tricolor. The hepatic caeca were fawn-coloured, 

 red at their extremities. Down the front of each of the cerata was 

 a streak of opalescent blue ; this characteristic coloration also ex- 

 isting, though more faintly, on the head, oral tentacles, and in 

 patches on the back of the body. There was a more or less regular 

 semilunar patch of opaque white on the anterior face of each of the 

 cerata near the tip, and this was generally continued as a streak 

 of white down the anterior face for a short distance. 



On October 8th, 1 890, a small specimen, not quite -^ inch in length, 

 was found again among Ohelia onLaminaria dredged intheCattewater. 

 The foot of this individual was broad and thin as in F. Drummondii, 



