REPORT ON icnxnYOLOGY. 429 



The I'hndodHS viscosiis of Kaiinesqiu', the type of his set-tion Leptups, appears to 

 be the young of Ilopladelm oUvaris. It is said to have a length of "only four inches", 

 and its color is "brown with bluisli and grayish shades covered Avith a clammy viscos- 

 ity". The head is described as being "very iiat, witli a longitudinal furrow above, 

 elongated"; the "anal has lifteen rays and the ventrals nine". Excej)! as to the 

 cephalic furrow, the description so far is not inconsistent with the Hoplaikhis olivaris, 

 Ijut the jaws are said to be "nearly equal" and "the upper hardly longer". This as 

 well as the furroA'\- on the head and the number of ra}'s in the anal fin might tempt us 

 to believe that it Avas the Noturm, but the caudal fin is said to be "unequally bilobed, 

 the upper smaller and white, and the ventrals have nine rays". It is therefore diiul)t- 

 fnlh' treated as identical with the Jfnphtdclits until the researches of a naturalist shall 

 sliow otherwise. It is not nu;ntioned by Dr. Kirtland. 



With sonic doul)t, we j'ield to the opinion of Dr. Kirtland that the I'hnelodus nehu- 

 losiis of Rafinesque is tlu; old of P. limosus. The species is said to attain a length of 

 from two to four feet. The description is certainl}- not very characteristic; the s])ecies 

 is said to di tier from the former by "the conical head, membranaceous operculum, but 

 particularly because the first ray of all the fins, except the caudal and adipose, is a kind 

 of soft obtuse spine, concealed under the fleshy cover of the fins". ( )n account of these 

 differences, it is suggested that the species ma)- l)elong to a "peculiar section or even 

 sub-genus", for which the name of Opiadcliiv is proposed. 



No description of the o))erculum or spines of I'imehdus vlscosus is given; it is 

 ))robable that the notes on the two "species" were taken at difterent times, and that 

 Hafiuesque's attention being arrested by the characters mentioned, and not l)elieving 

 that they could have been overlooked by him in tlie F'nnchdus ri.'iconus, ;issmn(^d that 

 a difterence existed. It is strange that the jaws should be described as equal, the head 

 simply as "conical depressed", and the l)ody as "conical tapeiing behind",* and, were 

 not .such statements made !)}• an author proverljial for inaccuracy, we might well be 

 excused for believing in the identity of Pimdodus ndndotius with a species like the 

 present. The assertion that there are only twelve anal rays may be explained by the 

 subsequent statement that all "the fins are very fat, thick, &c." The eyes of I'imclo- 

 dm nchuIosKS, as of P. viscosm, ai-e said to l)e roinid and small; those of our Jhiplade- 

 his are elliptical. 



By Dr. l\irt\and, the Piniclodiis nrhidosHs is considered as " merely the old" of 

 Pimelodiis limosus. He further remarks that " it is nnicli larger, and proportionally 

 shorter and broader, than the one figured (P. limosus). I have never seen the young 

 unless our present species be considered as such." 



The Silurus olivaris pre\iouslv mentioned is referred l)y Kafinescpie to his Pime- 

 lodiis -)icJ)ulosus. 



Placing much confidence in Dr. Kirtland's judgment, we have followed him in 

 regarding I'imehdus limosus and P. nehulosus as identical, but the remark regarding the 

 dirterence of form excites some suspicion as to his correctness. The degree of differ- 



* Ralinesfino probably intciidcil to be um'lerstood as riiferiing to tlio " couical " oiitliiio of tlio head as Het-u from 

 tbe sid(>, aiul tlio depressed dorsal surface. The mention of tlie body as " conical tapering boliind " also doubtless refers 

 to tbe later.al view. 



