i86 The Ottawa Naturalist. [November 



eton, which is most fully developed in Ceraiodus; these fins in 

 Lepidostren and Protopterus being- filamentous. The tail, as in 

 Chimajras, is diphycercal ; but in at least one extinct species : 

 Diptettis heliodus the tail was heterocercal. The scales are cycloid, 

 and in the several species they differ much in size. In general 

 shape and character Protopterus approaches more closely to Lepi- 

 dosiren than either do to Ceratodus. The scales in the two former 

 genera are small, whilst those of the latter are very large. Again 

 in the two former the vertical fin begins before the middle of the 

 fish, and, as has been stated, the paired fins are converted into 

 long filamentous organs ; whilst in the latter the vertical fin begins 

 behind the ventrals, which are placed of course as they are in all 

 Ganoids abdominally, and the paired fins ^re proportionately 

 shorter and paddle shaped. 



Unfortunately the specimen of Protopterus annectens, and 

 another for Prof. Ramsay Wright of Toronto University, which I 

 brought from Liverpool did not survive ; and on dissolving the 

 capsule the former had all the appearance of having been dead tor 

 some time. However, after placing the dead fish for a short time 

 in spirits diluted with water, I succeeded in sufficiently softening 

 out the specimen so as to enable me to make an examination of 

 its structure. 



This species is elongated and compressed in shape. The 

 gill-cleft and the eye are small. The filamentous pectorals and 

 ventrals are fringed down the sides — the fringes according in plan 

 with the rays of the verticle fin : which fin bears a multitude of 

 close fitting rays throughout its length. Adjacent to the gill-cleft 

 and immediately above the pectorals, there are branchial appen- 

 dages. The scales, being small, are numerous, and embedded in 

 the skin. Each jaw has a large tooth, a molar, with cusps. 



The following recorded characters of structure, in this speci- 

 men were more or less obscure, owing to its shriveled condition. 

 The lateral line runs nearly straight from the gill-cleft to the caudal 

 portion of the vertical fin. There are two pairs of nostrils. The 

 lung agrees with that oi Lepidosiren in being "divided into lateral 

 halves," and differs in that respect from Ceratodus in which genus 

 the lung is single. 



