I 70 Memoir Sears Foundatmi for Mari?ie Research 



on large; also, low down along either side of the tail of northern specimens there 

 are 1—2 rows, 2—4 on southern. The dorsal fins are uniformly prickly at all sizes 

 and in both sexes, the interspace between them having 1—3 thorns, larger or smaller. 

 Sexually mature males have about 25—40 large thorns on the marginal region on 

 each side about at the level of the eyes; the alar spines are arranged in 4—7 rows on 

 the outer parts of the pectorals, there being about 28 spines in the innermost (longest) 

 row. The lower surface on smaller specimens is smooth except for a prickly snout tip, 

 but with growth the head becomes roughened with prickles rearward in a narrow band 

 along the margins of the disc about to the level of the mouth on males, and a short 

 distance farther on some females. Females also develop a prickly patch close in front 

 of the axil of the pectoral. The lower surfaces of the pelvics are smooth on males but 

 more or less prickly on large females. 



Snout in front of orbits 2.7—3.1 times as long as distance between orbits; its 

 length in front of mouth 1.7—2.2 times as great as distance between exposed nostrils. 

 Orbit 1. 2-1. 4 times as long as spiracle; distance between orbits about 1.2 times as 

 great as length of orbit. 



Distance between first gill openings about 1.9— 2.1 times as long as distance 

 between exposed nostrils; fifth gill openings about 75 "/o as long as first; distance be- 

 tween fifth pair of gills i. 0—1.2 times as long as distance between exposed nostrils 

 and about 0.9—1.2 times as long as breadth of mouth. 



Nasal curtain fringed; expanded posterior (outer) margin of nostril also fringed. 

 Mouth nearly straight in females, only a little more arched in adult males. 



Teeth 48Z49 (four specimens) in transverse series, close-set, with low conical cusp, 

 blunter on older rows and sharper on younger; sharper also on mature males than on 

 females, especially along the younger (posterior) rows. 



First and second dorsals similar in size and shape; interspace between them 

 14-30 % as long as base of first dorsal. Caudal membrane from rear end of base of 

 second dorsal 32—53 "/o as long as base of first dorsal. Pelvics only moderately con- 

 cave outwardly, more or less scalloped, most strongly so at base of marginal concavity; 

 anterior margin about half as long as distance from origin of pelvic to rear tip; anterior 

 lobe fleshy with rounded tip, including 4—5 slender radial cartilages as well as the 

 first and stoutest; outer margin of posterior lobe nearly straight anteriorly, weakly 

 convex toward narrowly rounded rear tip. 



Anterior rays of pectorals extending about 55-65 "/o of distance from level of 

 fronts of orbits toward tip of snout. 



Color. A living specimen nearly three feet long, observed in an aquarium at Woods 

 Hole, Massachusetts, was dark and light brown above, with many roundish spots as 

 well as more elongate bars of the darker shade, and with irregular spots of the lighter 

 shade about ^U—\ inch across; these markings appear on the tail as wide dark brown 

 crossbars separated by light brown areas ; the disc, pelvics, lateral edges of tail, and dor- 

 sal outlined with a narrow band of white. There is a translucent space on either side 

 of the rostral ridge. The lower surface is white without dark markings. Other specimens 



