MR. A.LBEB OK T11K MOLLUSCA. I 



may be deducted five species, Murex erinaceus, Margarita cinerea, 

 Astarte elliptica, Mya Uddevallensis, and Saxicava sulcata, pre- 

 sumed to be fossil. This will leave 132 species; to which have 

 been added in the subsequent dredgings 32 species, making the 

 whole number 164, distributed as follows : — 



Cephalopoda 2 



Gasteropoda 84 



Lamellibranchiata 65 



Tunicata 13 



164 



Any comparison instituted between the species obtained in 

 these dredging expeditions and the Faunas of other marine 

 localities will be in some respects imperfect, inasmuch as they 

 represent only a part of our Fauna, the littoral and Laminarian 

 species being scarcely at all represented. Several important 

 deep-water species are also absent. On the whole, however, 

 they bear out the boreal character of the marine Invertebrata 

 of our coast. Taking the testaceous Mollusca alone for compari 

 son, as the naked Mollusks and Tunicates have scarcely been 

 sufficiently examined in northern latitudes, and are entirely ab- 

 sent in fossil beds, the following results have been obtained. The 

 Testacea met with amount to 135. Of these about 30 are now 

 living in the Arctic seas, and no less than 120 are found on the 

 shores of Norway and Sweden, leaving only 15, mostly very small 

 and inconspicuous kinds, that have not yet been detected in those 

 boreal regions. A somewhat larger number, about 20, and these 

 more conspicuous species, less likely to be overlooked, are absent 

 on the south coast of England. Upwards of 50 of our species are 

 met with in the glacial and post-pleiocene beds of this country, 

 and a large number, 82, are found fossil in the Crag. 



