42 INVERTEBRATE ANIMALS. 



IT Examples of Oleacina, Glandina, Discus, Zonites, 

 Vitrina, TestaceMa, Sagda, &c. Series related 

 to Testacella and Parmacella. 



dBlebmt^ Cable Cas^. 



The Mark ^ indicates specimens or other illustrations exhibited in the Cases. 



Group 121.— Family BELLEEOPHONTID^ (MacCoy). 

 Estimated number of species 70, known only as fossils, 

 chiefly Silurian and Carboniferous. The position of the 

 group is uncertain, the animal being quite unknown 

 except through the remains of its shell. Its place may 

 probably be with the Heterojjoda. 



Class CEPHALOPODA. 



xs<pa\Yj, the head ; ttovs, a foot. 

 Organs of progression encircling the head. 



Order TETRABRANCHIATA (Owen). Gills 

 4 ; arms many, without suckers, resembling tentacles. 

 The shells in this very extensive order, of which only a 

 single living form remains (the Nautilus), are all 

 chambered, i.e., divided transversely into compartments, 

 in the outermost of which the animal resides, keeping up 

 a communication with the previously inhabited chambers 

 by means of a siphuncle or tube. 



Family AMMONITIDiE (Owen). "AMMHN, 

 a title of Jupiter when represented as having the horns 

 of a ram. 



Group 122.--Genus HAMITES (Parkinson); and allies. 

 hamus, a hook. This group includes the genera of the 

 Ammonite family, in which the tube of the shell is 



