2. AMPHISII.E. 527 



the pectoral fin which equals that between the operciihim and tlie 

 pectoral ; a mdimentary pubic bone is visible within the fringe*. 



The vent is situated very far backwards, immediately before the 

 anal fin ; its distance from the base of the caudal is less than that 

 between opercle and pectoral. 



The colour of preserved spcimens is uniform whitish. 



Anatomy. — The first organ which makes its appearance after the 

 removal of the lateral portion of the cuirass is the air-bladder: its 

 position and its extent are easily ascertained by holding the fish 

 against the light, when an oblong oval spot will be \asible which is 

 more transparent than the rest ; it commences on the same level 

 with the root of the pectoral and extends backwards to the fourth 

 rib. The oesophagus passes gradually into the stomach, which is 

 situated below the air-bladder ; it does not appear to be much wider 

 than the intestine following ; the latter makes a single complete 

 circumvolution and then proceeds to the vent. Ovaria and testicles 

 are situated behind the air-bladder. 



The structure of the vertebral column is extremely singular, and 

 perhaps unique among the Acanthopterygians. The abdominal 

 portion is more than four times as long as the caudal ; nevertheless 

 it is composed of only six vertebrae, whilst the latter consists of 

 fourteen. These abdominal vertebrae are extremely slender, the 

 third alone being nearly as long as the whole caudal portion ; they 

 have a slight ridge superiorly and inferiorly and on each side ; the 

 whole portion lies in the uppermost concavitj- of the doi-sal cuirass. 

 The caudal vertebrae are extremely short, and the strength of their 

 neural and haemal spines is in proportion to their size. 



I am of opinion that the dorsal ciiirass is not a dermal production, 

 but formed by modified parts of the endoskcleton ; its composition, 

 the number and position of its single parts, and, finally, the first 

 dorsal spine, which in A. punctulata is so singularly attached to it, 

 favour this opinion. The plates which occupy the vertebral line 

 would correspond to the neural spines, and the lateral plates on 

 which the ribs are suspended, to the parapophyses. Amphisile may 

 be considered as a Chelonian form among fishes. 



2. Amphisile punctulata. 



Amphisile, sp., Klein, Miss. Piac. iv. p. 28. tab. 6. fig. 6. 

 ? Centriscus scutatus, Forsk. Descript. Anim. p. xvii. 

 Amphisile punctulata, Bianconi, Spec. Zuol. Mos. fasc. x. 1854, p. 221. 

 tab. 1. fig. 2. 



brevispinis, Peters in Wiegm. Arch, 1855, p. 259. 



pimctata, Kiier in Sitzgsbe'r. Wien. Acad. 1860, xxxix. p. 534. fig. 2. 



B. 4. D. 3 t 10. A. 13. C. 11. P. 12. V. 4. 



The first dorsal spine is joined to, and not quite half as long as, 

 its intemeural ; the distance of the posterior margin of the oper- 

 culum from the root of the pectoral equals its distance from the 



* According to JCner, the ventral fins are united and the middle rays are pp 

 longed in the male sex. 



