Mr. Robert Garner's Malacological Notes. 361 



due perhaps to the necessary arrangement of the inlets and 

 outlets of the body in such animals as are encased and pro- 

 tected by a shell or in other ways. Mr. Spencer attributes 

 the jointed form in the great subkingdom Articulata to repeti- 

 tion or buddingj yet of a less mechanical origin than the jointed 

 but adaptive disposition of the Vertebrata. Notwithstanding 

 this low vegetative characteristic of the Articulata, if it hold 

 good, they and Mollusca are commonly considered to form 

 two parallel zoological divisions, rather than one concatenated 

 series. Upon the whole, the Mollusca approach nearer to the 

 Vertebrata, as will become evident hereafter ; but the Articu- 

 lata are highly developed for locomotion, which ensures per- 

 fect mechanical structure and symmetry ; they are less gene- 

 rally aquatic, and often adapted for aerial movement, to 

 which last the Mollusca cannot fairly be said to attain ; they 

 also evince wonderful powers of what looks like observation 

 and purpose. At the saine time the Mollusca present varied 

 means of locomotion and of domiciling themselves ; and their 

 intelligence may be greater than our means of observation 

 enable us to ascertain ; the locomotion, however, with the ex- 

 ception of that of the pelagic swimmers, is generally of a simple 

 kind, mere gliding or creeping rather than walking, the 

 organs being formed with greater reference to hydraulics than 

 mechanics. They are anchorites accommodated to their cells, 

 sensitive rather than locomotive unities, seldom having any 

 repetition of parts of an analogous kind, but commonly 

 possessing, as already observed, more or less of that lateral 

 duplicity present in all animals above the Radiata — though, 

 indeed, in the Gastropoda this is liable to be interfered with 

 by an atrophy of one side. Altogether a mollusk is a typical 

 reality, showing either an origin from some primary molluscan 

 root, or a uniformity of special plan throughout their own 

 subkingdom. As a rule there may be said to be seen in them, 

 as we have them at present, an ascent from their lowest to 

 their highest forms, without any great hiatus — in this, more 

 than in their geological sequence, agreeing with the theory 

 of the derivation of one kind from another. 



If we are to trace up the Mollusca to their origin, their 

 biological pedigree, we shall, it is commonly held, arrive at 

 the Bryozoa, or rather, to our mind, at the lowest Ascidire. 

 It seems far-fetched to form an alliance, as Cuvier did, between 

 . the Teredo and the articulate Lepas, though there is an obvi- 

 ous analogy between the valves and adductor muscles of the 

 last and those of a bivalve mollusk — one of those curious 

 resemblances often occurring in nature between animals far 

 removed from cacli otlier, evincing, on the one hand, relation- 



