130 A Guide to the Zoological Collections in the 



in the two series ofCases I to VIII at the south end of the 

 Gallery, and IX — XV at the north end of the Gallery, by 

 a great variety of species from all parts of the world and 

 from all elevations, 



2. GLOSSOPHORA SCAPHOPODA. 



[OCaee 169JI]. 



In the very small Class of the Scaphopoda, or " Tooth- 

 shells ", the foot body and mantle are much elongated : 

 the opposite edges of the mantle meet and unite below 

 the foot to form a tube, on the outside of which a long 

 cylindrical pointed tusk-like shell is developed. The shells, 

 in fact, much resemble the calcareous tubes of certain 

 marine worms. The Scaphopoda, which are represented 

 in Case 169A by specimens of Dentalium, Cadulusy and 

 Entalis, live in the bed of the sea, burrowing in the sand 

 with their long scoop-like foot. 



3. GLOSSOPHORA CEPHALOPODA. 



[(Ea0£0 X69f — 171(E]. 



In this Class, the members of which are all marine and 

 freely locomotive, the foot is modified principally for 

 swimming, but also in part for prehension and for walk- 

 ing. Of the three regions of the foot the front region 

 (propodium) is fused with the head and is usually split 

 into fleshy prehensile " arms " of varying length ; the 

 middle region (mesopodium) is expanded on each side to 

 form either a pair of wings (epipodia), or, by the inrolling 

 of the wings and the apposition or actual union of their 

 edges, a short funnel ; while the after region (metapodium) 

 is small or absent. The mantle is usually well-developed, 

 and encloses a deep pocket-like mantle-chamber ; in one 

 group of Pteropods, however, it is altogether absent. The 

 shell varies ; when present it is always light, and is often 

 entirely concealed in a fold of the mantle. 



The Cephalopoda are divided by Professor Ray Lan- 

 kester into two branches or sub-Classes, namely (i) the 



