18fil.] DR. A. GiJNTHER ON THE ANATOMY OF MONITOR. 109 



some may be wholly absent. When this is the case (and it is the case 

 with the tail of the Phyllostomidce), it will only lead to error if made 

 use of as a means whereby to define minor groups. It is amongst 

 those characteristics which by their prominent development mark 

 out large groups of species, that we should look for the modifications 

 required for the definition of the smaller groups. 



2. On the Anatomy of Monitor niloticus from Western 

 Africa, and of Regenia albogularis. By Dr. Albert 

 GiJNTHER, For. Memb. Z.S. 



Several anatomists have examined specimens of the family of Mo- 

 nitores, and found important anatomical characters which appear to 

 be common to all the members of the family. Cuvier, Meckel, Stan- 

 nius, and others describe the structure of the tongue, of the salivary 

 glands, of the trachea, of the kidneys, &c. But few of them have 

 been careful enough in the determination of the species examined ; 

 and, although there is no doubt that, for instance, Cuvier had dis- 

 sected specimens of Monitor niloticus, it is evident that, under the 

 denomination of Tupinambis (as he calls the genus) *, he has con- 

 founded very different species, — a urinary bladder, which he ascribes 

 to that genus, not being found either in Regenia or in Monitor nilo- 

 ticus. 



The specimen of the latter animal which I have examined is 5 feet 

 long, and 1,5 inches in its greatest circumference. It was brought 

 to the Gardens at nearly the same time as the Regenia ocellataf, 

 and probably came from the same locahty. The habits of both 

 were very much alike, the Monitor more freely taking to the water. 

 Its food consisted of eggs and pieces of meat. 



The long, vermiform tongue terminates in two slender points, the 

 cartilaginous extremity of which is less prolonged than in Regenia ; 

 it is received posteriorly into a long sheath of the mucosa, whilst its 

 anterior portion moves in a longitudinal groove formed by the sali- 

 vary organs. The latter are composed first of an elongate glandu- 

 lary mass, situated below the tongue, and forming the bottom of that 

 groove ; it represents a glandula sublingualis, each single glandule 

 opening by a separate orifice. On each side of this gland, there is 

 situated another which is elongate like the former, but much thicker, 

 especially posteriorly ; it forms the lateral portion of that groove in 

 which the tongue moves, and can be considered either as a separate 

 division of the glandula sublingualis of higher animals or as a glan- 

 dula submaxillaris ; the ducts of its portions are united into several 

 short ducts, which empty the saliva through pores behind the front 

 teeth. There are, besides, numerous solitary glands, arranged in 

 longitudinal series. 



* VorlesuDg. in vergl. Anat. iibers. v. Froriep & Meckel, ii. p. 664. t. 15. f. 3; 

 iii. p. 201 ; iv. p. 641, etc. 

 t See antea, p. 60. 



