248 MR GOODSIR ON THE ANATOMY OF AMPHIOXUS LANCEOLATUS. 



the specific designation lanceolaris. Mr STEWART'S description is evidently an 

 abstract from that of PALLAS, to whom he refers. He had, however, a right ap- 

 preciation of the essential characters, as he states that the animal is " hardly a 

 Limax." 



It is to Mr YARRELL, however, in his most valuable work on British Fishes, 

 that we are indebted for the first detailed account of this animal. He recognised, 

 in his solitary specimen, the Limax lanceolatus of PALLAS. In his description, 

 which is in other respects most correct, he has omitted the lateral membranous 

 folds of the abdomen, so well observed and embodied in the description of PALLAS. 

 Mr YARRELL observed the vertebral column, the ichthyic lateral muscles, dorsal 

 fin, intestines, and ovaries, and transferred the animal, therefore, to the Verte- 

 brata. He placed it in the family Petromyzida?, near the cyclostomous fishes, as 

 he considered the fringed mouth, the armed lingual bone, the absence of eyes, and 

 the want of pectoral and ventral fins, to be structural characters sufficient to con- 

 nect it with the Lamprey and Myxine. For its reception he constituted a new 

 genus, AMPHIOXUS. and described the species under the designation lanceolatus, 

 looking upon it as the lowest in organization in the class of Fishes.* 



Mr COUCH, the indefatigable ichthyologist of Polperro, who supplied Mr 

 YARRELL with his specimen, published in the Magazine of Natural History, July 

 1838, a short paper, in which he gave some additional details of structure observed 

 before the animal had been immersed in spirits. He considered it to be a fish 

 with sixty vertebrae. He observed the anal fin, which had escaped Mr YARRELL 

 in the preserved specimen ; he also described what he considered an anomalous 

 kind of fin rays, in the form of transverse bows or arches, the curve forming the 

 support of the fin, the pillars probably resting on transverse spinous processes of 

 the vertebrae. He observed that these peculiar rays did not extend to the caudal 

 portion of either the dorsal or anal fins. In his second specimen, on which the 

 observations of structure were made, he could detect none of the ova which were 

 so conspicuous in the first. 



I was not aware till I had almost finished my examination of the Lancelet, 

 that any thing farther had been published on the subject. A few Aveeks ago, how- 

 ever, I observed in the Proceedings of the Berlin Academy for 1839,f an abstract 

 of a paper on Amphioxus lanceolatus by Professor MULLER. From this abstract 

 it appears that Professor RETZIUS of Stockholm has written a short memoir on the 

 subject, in which he has announced the fact, observed by himself and Professor 

 SANDEVALL, that the chorda dorsalis does not pass into a cranium, but terminates 

 at a point behind it. Professor RETZIUS describes the spinal marrow as termina- 

 ting considerably behind the anterior extremity of the chorda dorsalis, in a brain 



* YARRELL'S British Fishes, loc. cit. 



t Bericht iiber die zur Bekanntraachung geeigneten Verhandlungen der Konigl. Preuss. Akademie 

 der Wissenschaften zu Berlin. Nov. 1839, p. 197. 



