58 CLASS XIV. 



Compare on this genus : 



W. YARBELL History of British Fishes, n. 1836, pp. 468 477. 



H. EATHKE BemerTcungen uber den Bau des Amphioxus lanceolatw. Mit 

 einer Kupfertafel. Konigsberg, 1841. 



J. MUELLER Ueber den Bau u. die Lebenserscheinunyen des Branchio- 

 stoma lubricum COSTA. Mit 5 Kupfert. Berlin, 1844, 8vo. 



A. DE QUATREFAGES Mtmoire sur le systeme nerveux et sur Vhistoloyie 

 du Branchiostome ou Amphioxus, Ann. des Sc. not. 30 Se'rie, Tom. iv. 

 Zool. 1845, PP. 1 97 2 4-8, 1*1. 10 1 3- The descriptions of the Neapolitan 

 naturalist COSTA (Cenni Zoologici, 1834, Fauna del Reyno di Napoli, 1839), 

 are known to me from citations alone. Also of the paper of J. GOODSIR, 

 Trans, of the roy. Soc. of Edinburgh, xv. 1841, I have only been able to 

 consult the short account in the Ann. of not. Hist. vii. pp. 346 348. 



Sp. Amphioxus lanceolatus YARRELL, Branchiostoma lubricum. This species, 

 the only one as it seems of this genus, occurs in different seas, and nume- 

 rously in some places in the Mediterranean ; it buries itself in the sand of 

 the shore ; its length is from i ^ to 2". PALLAS, who first described and 

 figured it, held it to be a mollusc, whence he named it Limax lanceolatus. 

 Spicileg. Zoolog. Ease. x. Tab. i. fig. n. 



OEDEE II. Cyclostomi. 



Blood red. Heart distinct. Branchial artery without bulb, 

 furnished at the base with two valves. Body, cylindrical. Branchiae 

 furnished with external spiracles, sacciform, six or seven on each 

 side. 



Family II. Myxinoidei (Hyperotreta MUELL.). Body cylin- 

 drical, obliquely truncated anteriorly. Mouth anterior, cirrose ; 

 olfactory cavity furnished anteriorly with a tracheal tube leading to 

 an external aperture above the mouth, posteriorly with a canal 

 perforating the palate. Single horny tooth in palate ; smaller teeth 

 in a double row on each side in tongue, recurved. Branchiae on 

 each side with internal ducts leading to the oesophagus. 



The work of J. MUELLEK, already cited, Vergleichende Anatomie 

 der Myxinoiden, Abhand. der Koenigl. Akademie der Wissenschaften 

 zu Berlin, 1834, 1838, 1839, 1842, has, in particular, greatly 

 illustrated this family. The perforated palate, the connexion of 

 the cavities of the nose and the mouth, is not found in other fishes, 

 and is besides a common character of vertebrates that breathe by 

 lungs. The inferior margin of the mouth, since no under-jaw is 

 present, is formed by the anterior extremity of the tongue-bone. 



