FAUNISTIC NOTES AT PLYMOUTH DURING 1893—4. 219 
remarkable Ammotrypane aulogastra of Rathke (non Johnston) was 
dredged off the Duke Rock. 
Two specimens of the pelagic post-larval stage of Arenicola 
(described in this Journal, IIT, 1893, p. 48, by Dr. Benham) were 
again obtained this year in February, but about a fortnight earlier 
than in 1898. 
GupHyrea.—Phoronis hippocrepia has been frequently dredged, 
especially in Millbay Channel, and I have also taken it on the shore 
at Cremyll. 
Mo.iusca.—Several specimens of Lima Loscombii have been taken 
alive in about 20 fathoms off Stoke Point and south of the Mewstone. 
Large specimens of Arca tetragona can be obtained in Rum Bay by 
breaking the rocks there to pieces with a crowbar. They live in 
deep holes and crevices of the rocks, to which they are permanently 
attached by their stout operculum-like byssus. In the majority of 
cases the shells are remarkably abraded and polished by the efforts 
of the molluscs to enlarge the crevices in which they are fixed, so 
as to make room for their own increasing size. Not only is their 
layer of bristles entirely worn away in many cases by this friction of 
the valves against the surrounding rock, but the rock itself is rubbed 
away and polished by the incessant friction. In many cases I found 
the rock to be an almost perfect mould around the mollusc, while 
the aperture to the crevice by which the larval or young Arca had 
originally entered was not large enough to admit a specimen of even 
half the bulk to which the mollusc had attained ! 
A remarkably elongated specimen of Loligo media was trawled on 
April 14th, 1893, eight miles south of the breakwater. I took the 
following notes of its dimensions : 
Maximum length of mantle . ; . 136 mm. 
a breadth of fin : ‘ Pama Asia 
Anterior extremity of fin to apex ofbody. 98 ,, 
Posterior _,, Bs as bie Oe 43 ,, 
The extraordinary abundance of the Tectibranch Philine aperta 
during 1893 has been already mentioned. Hundreds of specimens 
could easily be obtained at any time in the eastern portion of the 
Sound, and the species with its gelatinous egg-masses was so 
abundant in July as to choke the meshes of the shrimp-trawl when 
worked in Jennycliff Bay. Oscaniws membranaceus also, though not 
so abundant as Philine, was unusually plentiful, especially in Mill- 
bay Channel and the Hamoaze. 
In February of this year I found a single specimen of an appa- 
rently undescribed * type of Tectibranchiate molluse which unites in 
* This is the Colpodaspis pusilla of Michael Sars, a very rare and interesting form, 
of which only two specimens have previously been obtained. 
