THE SEA-SCORPION FAMILY. 133 



region of the abdomen represents the yolk with its single 

 oil-globule (now minute). A feature which from the first was 

 most diagnostic was the dense black pigment of the lining 

 membrane of the abdominal roof, and it is outlined by a fringe 

 of yellow. A single ventral line of black chromatophores occurs 

 behind the vent. 



Forms somewhat older were caught in the bottom nets at the 

 beginning of May measuring 4-8 mm. (in spirit), and with well 

 marked embryonic rays in the tail. In these as well as in the 

 younger forms a curious separation of the black chromatophores 

 of the abdominal roof takes place. 



Mr Holt procured specimens of 6 25 and 7 mm. off the West 

 coast of Ireland ; while one of 8 mm. was formerly described 

 in the Researches^. The deep black patches of abdominal 

 pigment were very conspicuous. The head is greenish and the 

 body comparatively pale. The eyes, as in the common form, are 

 bluish, with a remarkable St Andrews cross radiating from the 

 pupil, the long axis being horizontal (Plate V, fig. 11). Stellate 

 black chromatophores occur on the under surface of the abdomen, 

 a touch of the same pigment at the anterior region of the 

 branchiostegal rays, and a row runs along the ventral edge of the 

 body above the anal fin. One or two specks are also present on 

 the cheeks, and a considerable number over the brain, the latter 

 being bounded by a curved line which joins a median black 

 band in front of the dorsal fin. The four tubercles on the head 

 are distinct, the posterior pair being the larger. The turbinal 

 spines are not visible; but the four on the anterior gill-cover 

 (pre-operculum) are well-marked, the superior being especially 

 evident. The first dorsal fin is only slightly arched, the second 

 is continuous posteriorly with the larval tail-fin, which now lies 

 at the upper angle. The permanent rays give a somewhat 

 conical shape to the tail ventrally. The anal is likewise joined 

 to the caudal. The breast-fins form fan-shaped organs, the rays 

 passing close to the surface of the body. The rays are massive 

 thout^h soft, and, as in the adult, present considerable free 

 portions at the tip. The ventrals are small, and arise somewhat 

 behind the bases of the pectorals. 



1 Trans. B. S. E. p. 862. 



