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 1 . 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 

 though 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. E. S. E. p. 862. 



