MOLLUSCA OF PLYMOUTH SOUND. 183 



Bay, in the Cattewater, on the north side of Drake's Island, and on 

 the rocks near the ladies' bathing place, and has been obtained 

 several times with the dredge off the Mewstone and in the estuary 

 of the Yealm. Mr. Heape trawled it several times in Wembury 

 Bay. It is subject to considerable variation, as Alder and Hancock 

 state. In August, 1888, an individual was taken from the north 

 side of Drake's Island which was irregularly spotted with black on a 

 white ground. There were minute yellow tubercles on the body. 

 The velar processes were two, with indication of a third, on the right 

 side, and three on the left. The branchial prominences of the epi- 

 podial ridges were normal. 



In May of this year a fine specimen from the Cattewater measured 

 just over one inch in length. 



On June 5th, from one and three quarter miles south of the Mew- 

 stone, was taken an individual of the variety mentioned in the Mono- 

 graph as possessing no tubercles on the back. There were eight 

 velar filaments, pigmented orange, and there was no pigment else- 

 •where. The gills and tentacles were normal ; indeed, as yet I have 

 seen no marked variation in the structure of these organs in this 

 species, though such variation occurs, according to Alder and Han- 

 cock. 



Another specimen of this variety was obtained on June 11th from 

 three miles south of the Mewstone. 



Young ones were obtained in tide-pools below the ladies' bathing 

 place in July last year. 



17. P. ocELLATA, A. and H. 



On March 6th was obtained one small specimen of this species 

 from near the Duke Rock Buoy, with the dredge. 



Late in June I found three individuals under a stone between 

 tide-marks on the shore under Mount Edgcumbe Park near the 

 " Bridge." On the same small flat stone was some spawn, one and 

 a half times coiled. 



Sub-order 2.— CERATONOTA, Lankester. 



Family— TBITOI^IIDM, Johnston. 



11. Teitonia, Cuvier. 



18. T. Hombergii, Cuvier. 



Not uncommon in deep water off the Eddystone, where it is 



