MODIOLARIA. ia! 
9 inches long, in 40 to 50 fathoms. This is the farthest 
south station at which I know it to have been found in 
abundance, so much so as to “make sad work with the 
dredges” (Leckenby and Marshall). The distribution is 
decidedly northern. 
Foreign localities—Maine (Gould and Say), Labrador 
(Whiteaves), Iceland (Steenstrup and Verkriizen), Spitz- 
bergen and the Siberian Seas (J/iddendorf and others), 
Vancouver (Carpenter), Norway (Loven and others). 
MopiouaRtiA, Beck. 
Modiolaria marmorata, Forbes. 
Mytilus marmoratus, Forbes; Mytilus discors, Montagu ; 
Crenella marmorata, Forbes and Hanley. 
Habitat—At the roots of Laminariz, and below stones, 
sparingly at low tide. Common in deeper water in the 
integument of Ascidia mentula, from a single individual of 
which I have extracted upwards of two dozen specimens, 
many of them large. 
This species is very plentiful at Cumbrae wherever 
Ascidia nentula is found. I have taken it also at Craig- 
more and Callum’s Hole, Bute; and at Moll Dhu, Loch 
Fyne. Landsborough states that Major Martin dredged it 
at Corriegills, Arran, “in the coriaceous coat of Ascidia 
rustica.” 2 
British Distribution.—Everywhere common. Very large 
specimens were obtained by Messrs. Leckenby and Marshall 
on the Dogger Bank. 
Foreign localities—Norway (Ashjérnsen and others), 
northern and southern coasts of Spain and Portugal 
(M Andrew), Mediterranean (Forbes and others), Canary 
Islands (M‘Andrew), North Western America (Carpenter). 
* Modiolaria discors, Linné. 
Mytilus discors, Linné; Mytilus discrepans, Montagu ; 
Crenella discors, Forbes and Hanley. 
Habitat.—In rock pools between half tide and low water, 
generally imbedded among the roots of Corallina officinalis 
or other small seaweeds. It is very common in such pools 
on the west side of the Battery Point, Cumbrae, where I 
obtained specimens measuring 4 inch by 4 inch, which are 
the largest in my possession. 
