4 THE VOYAGE OF H.M.S. CHALLENGER. 



B. TEOPICAL ATLANTIC. 



1. Surface Fishes collected at St Paul's Rocks. 



The Expedition landed on these craggy rocks of the Mid- Atlantic on August 27, 

 1873, and the ship remained moored to the rocks till the 29th. The sea round them is 

 described as abounding in fish, as is usual at such isolated localities. The 'fauna is 

 composed of West Indian forms, with some of the species hitherto found at Ascension 

 and St Helena ; and I have thought it instructive to enumerate them separately, 

 although evidently many more species might have been collected during a longer stay. 

 It is not surprising that a distinct, and apparently undescribed, species of the widely 

 spread genus Holoceiitrum should prove to be peculiar to this isolated locality. 



Holoce7itrum sancti pauli, n. sp. (PL I. fig. A). 



D. ii, A. T%, L. lat. 48, L. transv. 3l/8. The height of the body is two-fifths of the 



total length (without caudal), the length of the head one-third ; the interspace between 



the eyes is 5 in the latter (opercular spine included). The length of the snout is equal 



to the diameter of the eye, which is one-fourth of the length of the head ; the maxillary 



does not reach to the vertical from the centre of the eye. Operculum, with a strong 



and thick triangular spine, and with denticulations beneath ; preeopercular spine broad, 



flattened, and cleft, or bifurcate at its extremity ; its length is contained 3^ times in 



that of the posterior edge of the prseoperculum. The third and fourth dorsal sj^ines are 



the longest, a little less than half the length of the head ; soft dorsal rather elevated, 



more than half the height of the body ; caudal deeply forked, the upper lobe much 



longer than the lower ; third anal spine very strong, one-third of the height of the body. 



Ventral fins about three-fourths of the length of the head, terminating at a great distance 



from the anus ; pectoral shorter than the ventrals. Uniform red. Length of specimen 



16 inches. 



Caranx ascensionis, Forst. 



Glyphidodon saxatilis, L. 



Cossyphus rufus, L. 



Platyglossus cyanostigma, C. V. 



Enchelycore nigricans, Bonnat. 



Balistes huniva, Lac. 



2. Surface Fishes collected at the Island of Asceksion.^ 



On the return journey (April 1876) the Expedition remained several days at this 

 locality, so that the naturalists succeeded in obtaining a rather interesting series of its 



^ [Many of the fishes in this list were collected by Dr Drew, K.N., and sent home to Mr Murray after the 

 Challenger left.— C. Wy. T.] 



