PLYMOUTH MARINE INVERTEBRATE FAUNA. 167 



miliaris is often abundant, and both Asterias ruhens and A. glacialis 

 are generally taken as well as Ophiothrix fragilis. In addition to the 

 ordinary shallow-water crabs, Pilumnus hirtellus, Portunus arcuatus, 

 Macropodia rostratvs, Inachus dorynchus, and Hyas arancus are usually 

 found. Large specimens of Archidoris tuherculata are met with, and 

 Acmcca virginca, Cahjptrcva chinensis, and Acanthochites fas(icularis, each 

 in considerable numbers, are characteristic. Of Hydroids, large colonies 

 of Plumularia 2y'in')wta are the most abundant, whilst Hydradinia 

 echinata is plentiful on shells inhabited by Eupagurus Ber7ihardus. 

 Large specimens of Phallusia mamillata are frequent, as well as speci- 

 mens of Ascidiella aspcrsa. Polycirrus aurantiacus is very plentiful, 

 wliilst numbers of Phyllodocids and Syllids, as well as other small 

 Polycha-tes, hide amongst the stones and shells. Eurylcpta cormUa, 

 Linens marinns, and Prosthcccrceus vittatus are also generally to be found. 



In the Yealm Eiver itself, above the junction with Newton Creek, 

 there is a large oyster bed. 



Zostera Bed along the Southern Shore. — A Zostem bed lies close 

 to the southern shore at the mouth of the harbour, which can be most 

 usefully worked with a shrimp trawl. Its fauna resembles that of the 

 Zostera bed in Cawsand Bay, to be mentioned later. In addition to 

 pipe-fishes, wrasse, and other small fishes, Macromysi? flexuosa is 

 abundant, as well as HippoJytc varians, Calliostoma striatum, Lacuna 

 divaricata, and Haliclystus auricula, whilst small Anemonin sulcdta are 

 abundant attached to the Zostera. 



OUTSIDE GROUNDS. 



Shores. 



Wembury Bay. The shores of this bay form one of the best 

 collecting grounds on the open coast in the neighbourhood of Plymouth. 

 A reef of high rocks (Church lieef and Blackstone Piocks) runs seawards 

 in a south-westerly direction from in front of Wembury Church, forming 

 deep overhanging ledges on the landward side, and leaving at low 

 water many tide-pools both large and small. To the westward of this 

 reef the shore is formed of stretches of low, weed-covered rocks 

 alternating with patches of gravel and sand of different textures. Tiie 

 whole shore is exposed to almost the full force of the Channel waves, 

 and the greater part of the fauna is found beneath the overhanging 

 ledges and in other sheltered situations amongst the rocks and seaweeds, 

 The fauna of the sand and gravel is not very extensive. 



The general character of the fauna of the rock ledges and of tlie 

 rock pools is similar to that found in corresponding situations within 

 the Sound {e.g Rum 15ay, Drake's Island), but there is greater profusion 



