1898.] PLANKTON OF THE FAEROE CHANNEL. 561 



a thickened fleshy rim. They are situate at about the middle of 

 the total length of the larva, and well behind the middle of the 

 abdominal region. The liver occurs as a small pyriform mass 

 shortly behind the clavicle. The alimentary canal, apparently 

 wide and thin-walled in the thoracic region, is soon constricted 

 and thickened. Its ventral wall shows a downward crenulation 

 (about halfway between the clavicle and the pelvics) which may 

 be accidental. At the pelvic region commences a well-marked 

 intestinal tract lined with transverse (annular, perhaps spiral) 

 ridges. The short and rather voluminous rectum leaves the 

 trunk in an oblique direction. 



There are 47 abdominal (counted to the origin of the rectum) 

 and 20 caudal myomeres visible : others may probably be seen 

 at a later stage, but the total number will not be much greater 

 than 67. Black pigment is present in a series of ventral spots, 

 seven in number, distributed at regular intervals from the 

 clavicular region backward. These consist for the most part of a 

 single chromatophore on either side of the gut, but at the shoulder 

 there are several, as also at the region of the rectal valve. The 

 pre-peduncular spot of the tail consists of two ventral and one 

 lateral chromatophore. The caudal fin, both as to the embryonic 

 and permanent parts, is rather profusely decorated with small 

 black dots. The eyes are deeply pigmented. The dorsal marginal 

 fin is wide. Anteriorly it is rather imperfect in the specimen 

 figured. In that of about 19 mm. the fin appears to be ampulla! e 

 anteriorly, and this is probably the natural condition in the others 

 also. There are no signs of the permanent dorsal and anal fins, 

 but embryonic rays occur in the postanal region. 



On comparison of the three examples it would appear that the 

 ventral spots become reduced as development advances. Though 

 identical in number those of the largest individual are relatively 

 considerably smaller than those of the younger. 



I have noticed elsewhere (p. 565 infra) the occurrence in 

 Dr. Fowler's collection of a pelagic egg, which, as far as may be 

 judged from the preserved condition, appears to be practically 

 identical with Baffaele's species No. 7 (Mitth, zool. Stat. Neap, 

 viii. 1888, p. 69). In conformation and in distribution of: pigment 

 the form which we are now dealing with bears a striking likeness 

 to the larva of Sp. 7 (op. cit. tav. v. fig. 9). The ventral spots are 

 numerically equal, and there is an indication in the Faeroe larva of 

 the large " rhomboidal " supra-cephalic sinus described in Sp. 7. 

 The latter is stated to have 59 or 60 abdominal segments, a 

 condition which indicates that the total number is considerably 

 in excess of that present in the much more advanced Faeroe larva, 

 and so disposes of the possibility of the formula being harmonized 

 in the two forms by a developmental migration of the anus. The 

 marginal fin, though wider in the Faeroe larva), terminates, in the 

 youngest example, as in Sp. 7 ; and in the anterior dorsal region 

 appears to be inflated alike in both forms. But none of the 

 Faeroe larvae show any trace of the prodigious buccal armature of 

 Sp. 7. The teeth, on the contrary, are quite small.! 



