Royal Academy of Sciences of Paris. 159 



details on the variations in the size and developement of the 

 sub-maxillary or common salivary gland, depending on the existence 

 or non-existence of a venomous gland. All M. Schlegel's observa- 

 tions on the difference and co-existence of the two glands had been 

 previously noticed by M. Duvernoy, who adds to them several new 

 remarks, particularly respecting the muscle of the venomous gland, 

 which appears to be an external temporal muscle, generally attached 

 to the envelope of the gland, and descending to .the lower jaw, 

 without being attached to the top of the temporal fossa, but occa- 

 sionally, as in the naia and the bougares, composed of two distinct 

 portions. His most particular attention, however, was directed to 

 the serpents having the long back teeth, for the purpose of ascer- 

 taining in which of them there exists the venomous gland, and in 

 which this elongation of the teeth does not denote any specific se- 

 cretion. When this gland does exist, it is frequently joined to the 

 sub-maxillary gland by a very thick cellular tissue, and may, there- 

 fore, be easily confounded with it. The existence of this gland is 

 certain in the coluber Esculapii of Linnaeus, in the coluber cerberus 

 of Dandin and Cuvier, the homalopsis pantherinus of Boye, and 

 in a dipsas, the baugarus interruptus of Oppel ; all those, there- 

 fore, are venomous, and illustrate the observations of M. Boye, who 

 had ascertained, from experiments made while the reptiles were 

 living, that the dipsas and the homalopsis are venomous. The 

 genera dendrophis, dryenus, and ocenodon have also the back teeth 

 large, and even in the dryenus nascetus, the largest tooth is hol- 

 lowed like a canal ; but as M. Duvernoy has not found any specific 

 or venomous gland, he concludes that they are not poisonous. 

 These circumstances explain the contradictory testimony existing 

 respecting the venomous qualities of particular serpents, and at the 

 same time prove that the class in question must be far less dan- 

 gerous than those in which the fang conducting the poison is in 

 front, because unless the object bitten be sufficiently small to admit 

 of its being taken into the mouth of the serpent, and thus brought 

 into contact with the back fang, no poison will be communicated to 

 it, and only a common wound be produced ; so that a person bitten 

 in the leg or arm would suffer no injury beyond the actual bite, while 

 another, whose finger was inserted into the mouth of the reptile, 

 would be poisoned. Hence, M. Duvernoy concludes that the prin- 

 cipal use of these posterior fangs is to kill the small animals which 

 the serpents take into their mouths alive, and that they are not of 

 much advantage as a means of attack or defence against external 

 enemies. In the course of his Memoir, M. Duvernoy remarks, that 

 in many serpents the spleen is closely attached to the pancreas, 

 which probably led M. Mecke) into the error of doubting its exist- 

 ence. This memoir was ordered to be inserted in the * llecueil des 

 Savans Etrangers,' and the various preparations presented to illus- 

 trate the subject were deposited in the Gallery of Anatomy in the 

 Museum of Natural History. 



