PLYMOUTH MARINE INVERTEBRATE FAUNA. 169 



Whitsand Bay. Depth 4-8 fms. Another example of a shallow 

 sandy bay, but being open to the south and west, it is subject to much 

 more disturbance from the waves than Cawsand Bay. There is here 

 also a great variety of the smaller Crustacea and Sepiola atlantica is 

 abundant. Cori/stes cassivelaunus and Astropecten irregidaris, character- 

 istic sand-dwelling species, are often taken in this bay, though much less 

 frequently than in deeper water. 



Mewstone Ledge. Depth 10-15 fms. A ridge of soft, red 

 conglomerate rock runs seawards in a southerly direction from the 

 Mewstone. Over this ridge at a depth of 10 to 12 fms. it is possible 

 to work a dredge, the dredge often breaking away and bringing to the 

 surface pieces of the rock of considerable size. The rock is free from 

 the growth of any seaweeds, but is well covered with Hydroids, Polyzoa, 

 and sponges. The following species are common and typical of the 

 fauna associated with this red rock : Eunicella verrucosa with Gephyra 

 Lohrni and Tritonia pkhcia living upon it ; Alcyonium digitatum with 

 Ovvla imtulct; Caryophyllia Siiiithi with its associated barnacle Pyrgoma 

 anglicum; Antennidaria antennina a,nd A. ram osa with Scalpellum vnlgare ; 

 small colonies of Sertutarella Gayi and S.jiolyzojiias; Phiniularia pinnata 

 and P. Catharina; Lafoea dumosa with occasional specimens of Myzomenia 

 hanyidensis attached ; Cacumaria hrunnea on the rock itself and on the 

 attached Hydroids ; occasional specimens of Antedon rosacea, Opliiothrb: 

 fmgilis, Henricia sanguinolenta, and of the large YioloWwwi^n, Holotlniria 

 nigra ; OpMopsila aranea concealed in holes and crevices of the rock ; 

 Pludlusia mamUlata, Ascidiella scahra, and Ciona intestincdis (small 

 specimens) ; the Polyzoa Crista corimta and Bugida JlahelUda in abund- 

 ance, Alcyonidium gc/atinosum, Bicellaria cUicda, small colonies of 

 Cellaria Jistidosa and C. sinuosa, and occasional large masses of Lepralia 

 foliacca, amongst which a number of small Crustacea, especially large 

 numbers of Poixellana longicornis, are to be found. The large Phyllodoce 

 Paretti is also often found here. The red rock itself is bored by numbers 

 of Pholadidea loscomhiana. 



Mewstone Shell Gravel. On either side of the Mewstone ledge, 

 and probably in patches between the rocks and the ledge, the bottom 

 soil is composed of a coarse shell gravel. In working a dredge over 

 the ledge a mixed fauna, comprising the animals from the rocks and 

 from the gravel, is generally obtained. The gravel itself may also 

 be worked with a small trawl, the Agassiz trawl having been generally 

 used in our work. 



Species characteristic of this shell gravel are Holothuria nigra (often 

 in considerable numbers), Cardium norvcgicum, Spatangus purpureus, 

 Glycimeris glycimeris, Zumbriconereis impatiens, Ghjccra gigantea, Aylao- 

 plienia myriophyllu7n, and Eurynome aspera. 



