PISCES. 79 



Mold NARDO. 

 Sp. Cephalus mola Risso, Mola luna NABDO. 



Molacanihus S WAINS., Palladia NARDO. 



Sp. Molacanthus Pallasii SWAINS., Diodon mola PALL., Spirit. Zool. vm. 

 Tab. 4, fig. 7. 



Diodon L. Maxillae undivided. Body everywhere dotted with 

 sharp spines. Dorsal fin small, remote, opposite to anal. 



Urchin- fishes. They are able to inflate themselves by taking air into their 

 spacious stomach, and then swim belly upwards. In addition they have a 

 swimming-bladder divided into two lobes. 



Compare on this genus CUVIEB Mem. du Mus. rv. 1818, pp. 121 138, 

 Tab. vi. vii. In some the spines are three-sided, or strongly carinate, as 

 in Diodon tigrinus Cuv. R. Ani., ed. ill., Poiss. PL in. fig. 3, from the E. 

 Indian Sea, and in another from S. America ; all of these are conjoined by 

 LINNJEUS as Diodon atringa (doubtless a misprint for Atinga). 



In addition there are species with long round quills, like those of the 

 hedgehog, Diodon hystrix L., Diodon punctatus Cuv., BLOCH Ichth. Tab. 

 1 26, from the Indian Ocean. Finally, there is a species with fine spines 

 like needles, Diodon pilosus MITCHILL. 



Triodon Cuv. Upper jaw bipartite, lower entire. Body muri- 

 cate with short spines. Pendulous sac beneath the body. (Ol- 

 factory organ perforate in front and behind.) 



Sp. Triodon bursarius Cuv., Tetrodon bursarius REINW., Triodon macro- 

 pterus LESS, and GABN., Voyage de DUPERBEY, Poiss. No. 4, Cuv. R. Ani., 

 ed. iU., PL 112, fig. i, from the E. Indian Sea. See CAM. DABESTE Ob- 

 servations sur VOsteologie du Poisson appele Triodon macropterus. Ann. des 

 Sc. nat. 36 Se"rie, Zoolog. Tom. xn. 1849, PP- 68 83, PL I. fig. i. 



Tetrodon L. Both jaws bipartite. Body muricate with short 

 spines, especially below. (Olfactory organ representing in many a 



cirrus or tentacle.) 



Four-tooth or Spine-belly. There are five rays in the branchial membrane. 

 The head is usually short and blunt. The spines are very -various ; some- 

 times they are entirely absent on the back. The olfactory organ presents 

 itself in many as a sulcated or fissured appendage in front of and above the 

 eyes, Tetrodon lineatus L. In some it is a very small channel like the prick 

 of a pin, with everted margin, as in Tetrodon rostratus, BLOCH Ichth. Tab. 

 146, fig. 2 ; in others a large, wide cavity, with folded margins, as in Tetro- 

 don grandispina, a new species from Borneo in the Leyden Museum (Che- 

 lonodon MUELLEB). Others have imperforate tentacula, in which the 

 olfactory nerve is situated (Arothon MUELLEB). Others, finally, would 



