14 Memoir Sears Foundation for Marine Research 



Distinctive Characters. B. carihaeum differs from B. lanceolatum and from B. africae 

 in that its anus is about in the middle of the lower lobe of the caudal fin. It is distinguished 

 from B. bermudae by the shape of the caudal fin and by the origin of the ventral lobe below 

 that of the dorsal lobe j by the position of the anus, in advance of the midpoint of the lower 

 lobe of the caudal finj and by the generally greater number of myotomes and dorsal fin- 

 ray chambers (at least 230 of the latter). It is separated from B. flatae by the shape of the 

 caudal fin, as well as by the position of the anus and by its tendency to have fewer myotomes 

 and dorsal fin-ray chambers. 



Additional Description. Anterior end of notochord in rostrum extending forward 

 in a straight line 5 rostrum marked ofF from dorsal fin by a subtriangular notch; caudal fin 

 symmetrically lanceolate with narrowly rounded tip, its lower lobe considerably higher 

 than ventral or dorsal fins, its origin opposite origin of its upper lobe and about midway 

 between tip of caudal fin and atriopore; distance from tip of caudal to anus about V3 dis- 

 tance from anus to atriopore; dorsal fin Ys as high as distance from its crest to margins of 

 metapleura in midregion of body; highest dorsal ray chambers 5 to 8 times as high as 

 long; dorsal ray chambers 230 to 320; precaudal (ventral) fin-ray chambers 18 to 37; 

 35 to 38 myotomes anterior to atriopore, 13 to 17 between atriopore and anus, and 6 to 9 

 posterior to anus, recorded totals, 57 to 64; gonads 22 to 29. 



Recorded counts for specimens from different localities. 



Color. Live specimens are flesh-color or semitransparent, with a metallic iridescence; 

 those kept in alcohol become opaque and whitish. 



Size. The greatest length so far recorded is 66 mm. (see Study Material, p. 13). 



Developmental Stages. In the Chesapeake region the pelagic larvae, of the sort 

 usual for the group (p. 5), tend to settle to the bottom by the time they have reached 

 a length of about 7.5 to 8 mm.^* 



Habits. The adults, like those of other species, live buried in coarse or fine sand. In 

 Florida, and presumably elsewhere also, they are most numerous along the edges of sand 

 bars just below the low tide mark where their presence is indicated by small holes in the 

 sand. If the sand is laid bare by a low run of tides it appears that they simply burrow more 



25. Andrews (Stud. Biol. Lab. Johns Hopk. Univ., 5, 1893: 241) reports a total of only 48 myotomes for a speci- 

 men from Jamaica. But this is so much fewer than any other recorded count that we judge it to have been erro- 

 neous; see also Franz (Jena Z. Naturw., 5*, 1922: 399). 



26. See Rice (Amer. Nat., t^, 1880: 17, pi. i, fig. 5) for a good illustration of the late larva. 



