1G8 FAUKISTIC NOTES. 



irregularity in their arrangement. It is usually possible, however, 

 to recognise two longitudinal rows of particularly large tubercles, three 

 or four on each side, which extend from the rhinophores to the peri- 

 branchial fossa. These two rows of large tubercles are situated along 

 a pair of lines which are the sites of tubercular or pigmented modifi- 

 cations in certain other types of Dorididce, e.y. the sub-lateral rows 

 of filaments on the back of Idalia Lcachii, and the post-rhinophoral 

 rows of pigment-patches in Doris {Jorunna) Johnstoiii. In Doris 

 maculata there is also an irregular median series of tubercles, as well as 

 a number of smaller lateral tubercles irregularly scattered over the back 

 between the main sub-lateral rows and the margin of the notseum. 



The tubercles are of a deep purple colour, due to granular deposits of 

 a purple pigment. 



The ridges which connect neighbouring tubercles with one another 

 are often slightly granulated with the same purple pigment. 



In specimens in which the serial arrangement of the tubercles is 

 not well defined, the general appearance is that of a central network 

 of ridges, radiating out into irregular lines at the sides. The tubercles 

 arise from the nodes of the network. 



Since the general colour of the body is bright yellow, the contrast 

 effected by the purple tubercles and ridges renders this little creature 

 a very striking object in a mass of dredged material ; it is, moreover, 

 easily recognised as distinct from any British Doris hitherto described. 



Doris maculata was first found by me at Plymouth on December 

 18th, 1893, when two specimens were dredged. It has since been 

 obtained on several occasions, but always from the same locality — 

 the western part of Plymouth Sound, known as the New and Queen's 

 Grounds. The bottom here is clean, and consists largely of hard rock 

 and stones, which graduate into beds of shells to the south. The flora 

 and fauna are characterized by the occurrence of Dclcsseria, Anten- 

 nularia, numerous Pohjzoa, and Morcliellium argus. 



W. Gakstang. 



On the changes in the Pelagic Fauna of Plymouth during 

 September, 1893 and 1895.— During a visit to the Plymouth 

 Laboratory, in September, 1893, and in September, 1895, for 

 systematic work on medusa3, it was almost a daily occupation to 

 examine with a microscope the contents of the tow-net, for the 

 purpose of obtaining the earliest stages of medusa?. Whilst thus 

 occupied, I noted down not only the meduste seen, but also other 

 pelagic animals. I propose to give here a few notes to show the 

 change in the pelagic fauna for the same month in different years. This 



