612 MK. R. H. WHITEHOUSE ON THE [Apr. 5, 



Cantharus vlluakis, (Percifoimes, Spaxidie.) 



The urostyle is well marked and free, and four hypurals are 

 attached to the last vertebral segment ; in all there are six 

 livpuials, the second and third last vertebra? each bearing one. 

 Epaxially, there ai-e three doi-sal caudal radials, and one epural 

 which is attached to the antepenultimate vertebi'a. The neural 

 arch of the penultimate vertebra is reduced, between the last 

 dorsal radial and the last hypm'al is a splint-like bone, the 

 proximal end of which I'ests on the dorsal end of the urostyle ; it 

 protects the ending of the spinal cord and is probably a neural 

 arch. The fin, therefore, is homocercal. 



Box salpa. (Perciformes, Sparida>.) (Plate XLIX. fig. 20.) 



The ui'ostyle is well marlced and distinct. Corresponding with 

 the last vertebral segment are three hypurals, two of which are 

 large, and the most anteiior is provided with a ridge for the 

 attachment of muscles ; there are five hypural bones in all ; 

 between the distal ends of the first two is a small cartilage 

 bearing a few of the small anterior hypaxial rays ; a very small 

 similar one is present on the anterior side of the first hypural. 

 Epaxialiy, there are three dorsal caudal I'adials (d.c.r.), while the 

 antepenultimate vertebra, bears an epural bone; this epural is 

 particularly interesting from the fact that in an animal 4 cm. 

 long (fig. 20) it is seen to be two distinct and separ-ate pieces — 

 a neural arch, exactly similar to that of the penultimate vertebra, 

 and a long cartilaginous radial, the proximal end of which is 

 slightly applied to the posterior edge of the neural spine. In the 

 adult, these two elements completely fuse to form an epural. 

 A neural arch is present on the last centrum. 



The caudal fin of Box is therefore homocercal, and slightly 

 more specialized than that of Cantjuiras, on account of the fewer 

 hypuials to the last vertebral segment. 



Smaris alcejdo. (Perciformes, Ma^nid;e,) 



A fairly long and free urostyle is present, (,)n the venti'al side 

 of which, together with the last centrum, are four fin-ray supports, 

 three only of which are undoubted hypural bones ; the last is 

 .somewhat doubtful. Both the penultimate and antepenultimate 

 vertebra? bear hypurals, between the distal ends of which is a 

 large cartilage bearing small fin-rays. Separated from this car- 

 tilage only ))y tlip distal end of the first hypural are two small 

 caitilages, both of which support the very small anterior epaxial 

 lin-rays; a similar cartilage dor-sally performs the same function. 

 Three definite dorsal caudal radials are present and one e])ural 

 l)one ; neural arches are borne by each of the last two vertebise. 

 A splint-like bone is cloj-iely fitted l)etween the distal ends of the 

 urostyle and the neui'al .-ircli of the last centrum ; pr<)bal)ly it is 

 a neural arch it.self, Vielonging to nome vei'tcbra, now aljsoi'licd 

 into the niostyle. Cartilaginous cpiphy.scs aii- jirescnt on most 



