212 Botanical Society of Edinburgh, 



nities, that it must be regarded as a true fish. The body of the tooth 

 consists of a coarse dentine traversed by numerous large anastomosing 

 medullary canals, without any trace of Purkinjian corpuscles : this 

 is coated by a thin layer of dense dentine, traversed by fine calcige- 

 rous tubes continued from the peripheral loops of the medullary 

 canal. 



This structure agrees with that modification which is most charac- 

 teristic of the class of Fishes, and has not been found in the teeth of 

 any of the Perennibranchiate Reptiles. The cumulative evidence of 

 this fact, with the ichthyic type of the microscopic structure of the 

 ossified parts of the skeleton ; the disposition of these parts, forming 

 double superior and inferior spinous processes, a pre-opercular bone, 

 and their green colour ; the gelatino-cartilaginous vertebral style ; the 

 many -jointed ray of the rudimentary fin ; large cycloid scales ; the in- 

 testinal spiral valve ; six pairs of branchial arches, with gills concealed 

 and protected by an operculum ; the blind nasal plicated sacs : these, 

 receiving the additional evidence from the intimate structure, as be- 

 fore from the form, number and attachment of the teeth, must out- 

 weigh the argument for its amphibious character, which is supported 

 only by the lung-like structure of its divided air-bladder, — a structure 

 which some Medacopterygious Sauroid fishes possess in common with 

 the Lepidosiren. 



Professor Ehrenberg of Berlin, and Professor Purkinje of Breslau, 

 were elected Honorary Members, and Daniel Cooper, Esq., an Ordi- 

 nary Member of the Society. 



March 17. — George Loddiges, Esq., in the Chair. 



A paper was read by George Busk, Esq., of the hospital-ship 

 Dreadnought, " On the Anatomy of Tricocephalus dispar" in which 

 the author directs attention to certain points in the anatomy of that 

 Entozoon, upon which all helminthologists appear to have erred. 



The author, after describing minutely the structure and arrange- 

 ment of the digestive and generative systems, arrives at the following 

 conclusions ; — 1st. That the Tricocephalus has a distinct vulva, and 

 that the generative and digestive tubes do not communicate at a 

 cloaca, nor terminate at a common orifice, as described by all writers 

 on the subject. 2nd. That in the presence and situation of the vulva 

 this Entozoon obviously very closely resembles the Strongylus and 

 most other nemgitoid worms, and thus an apparently great anomaly 

 in the arrangement of this class is removed. 3rd. That the ali- 

 mentary canal is not so simple as is commonly supposed. 4th. That 

 the Tricocephalus is in all probability simply oviparous, and that the 

 ova become perfectly formed only a short distance from the orifice, 

 perhaps from being there only within reach of the male fluid. 



BOTANICAL. SOCIETY OF EDINBURGH. 



March 25, 1841. — Dr. James Macaulay in the Chair. 

 The following communications were read : — 

 1. Notice oi Cai^um bulbocastanum, Koch, from two English lo- 

 calities, by Mr. Isaac Brown, Hitchin, Herts. Mr. Brown pointed 



