6 GENUS FIROLA. 



Organs of Locomotion, Fins two; dorsal one large, 

 rounded, moved by twenty pair of compressed muscles, 

 each terminating in a bifurcated point, and united in that 

 part of the opposite muscle, confluent at base, and fur- 

 iiished with two radicles, which penetrate the body be- 

 tween the peritoneum ^nd the exterior gelatinous sub- 

 stance. Caudal fin very s^ail, lobated or rounded, in- 

 cluding small ramose vessels, and moved by three pairs 

 of muscles, at their extremities filiform and united in a 

 common point. I have not been able to perceive any dis- 

 tinct muscles in other parts of the body, excepting those 

 already mentioned, and numerous oblique ones between 

 the peritoneum and the gelatinous exterior. 



Amongst a great number of individuals which I have 

 examined, the number and situation of the organs or 

 appendages, the presence or abseiice of either of them, 

 ha\,.^ furnished me with good specific characters. Of 

 the:5e I have availed myself to establish the follow^ing six 

 species, 



1. F, mutica. No vermiform organ; no cup on the 

 dorsal fin; no caudal appendage. Plate I. fig. 1. 



Substance firm, diaphanous, tuberculated, rosaceous; 

 tubercles irregularly placed, and of a deeper colour. Dor- 

 sal fin nearer tlie nucleus, placed in a groove. Trunk 

 "wrinkled, and with the region of the dorsal fin spotted 

 i/ith white. Gelatinous points six, disposed by opposite 

 pairs in two longitudinal lines. 



2. F, gibbosa. Body furnished with a vermiform or- 

 gan; no cuj^or caudal appendage. Plate I. fig. 2. 



Body gibbose above the nucleus, narrowed behind 

 the (^3 cs, and tmurginate at the base of the dorsal fin. 



