438 THE OPISTHOBRANCHTATE 



seven rows, tlie other eight, of cerata. In tlie latter specimen there 

 was one reticulating violet spot on the anterior part of the back, and 

 another more compact orange spot about the middle. The fourth 

 individual was white, with orange-tipped cerata. The oral ten- 

 tacles were entirely orange-coloured. The distal halves of the 

 rhinophores were orange-coloured, the proximal white. The back 

 showed a number of orange-coloured spots and faint traces of violet. 



When an individual of this species is in motion the oral tentacles 

 are kept in a nearly horizontal plane, constantly touching the sur- 

 face upon which the animal is creeping ; on the other hand, the 

 rhinophores are kept erect, extending outwards and somewhat for- 

 wards, in this way testing obstacles in the water, which are out of 

 the range of the oral tentacles. If the tentacles or dorsal integu- 

 ment be touched, the animal at once contracts and erects its cerata : 

 this reaction cannot usually be produced by touching the cerata 

 themselves, which possess little power of sensation. There is a slight 

 break in the regular sequence of the rows of cerata after the fourth 

 (or sometimes the third) row ; here the heart may be seen beating. 



The curious fact that all the specimens of this -^olid obtained by 

 us in 1888 and 1889 were found during a limited period in late autumn, 

 from the end of September to the commencement of November, 

 coupled with the fact that the individuals taken at the beginning of 

 this pei'iodwere slightly smaller in size than those found in November, 

 led me to make particular search for the species during the spring 

 of this year. I examined repeatedly blades of Laminaria for this 

 purpose, but found not a single specimen, but a bottom tow-net 

 devised by Mr. Cunningham and worked in Cawsand Bay during 

 May and June brought up, among the filamentous algae so abun- 

 dant there, a number of -Solids which I cannot but regard as the 

 more advanced stages in the growth of this species. I was unable 

 to devote much attention to them, but give here some notes drawn 

 up after an examination of two individuals. 



Rhinophores long ; almost, if not quite, equalled in length by the 

 oral tentacles. Cerata in about nine or more rows, four cerata in 

 each lateral half of a transverse row, perhaps five in some, the 

 external cerata being much smaller than the internal ; inflated, semi- 

 transparent, with tips orange-coloured in one specimen, whitish in 

 the other. Hepatic caeca slender, sacculated, running up to the tips 

 of the cerata; over the cerata a faint sage-green pigment spread. 

 Body very slender when thoroughly entended, approaching | inch 

 in length. The back covered with large conspicuous orange-red or 

 almost crimson spots, each spot surrounded by an area of sage-green 

 pigment consisting of a mass of microscopic sage-green dots. 

 These also give rise to the faint sage-green pigment of the cerata. 



