IN THE SOUTH-WESTEKN DISTRICT. 115 



the urochord with its embryonic rays being boldly thrust upwards by 

 the hypural mass, the margin of which is still oblique. The caudal 

 part of the trunk is most elevated at about half-way from the anal 

 region to the caudal peduncle ; on the slightly salient dorsal and 

 ventral edges appear the interspiuous ridges of the future second 

 dorsal and anal fins. Each ridge (dorsal and anal) is continuous, but 

 while the basal lobes of the anterior part are closely crowded together 

 the most posterior of the series appear as rather widely separate 

 nodules, or elevations of the crest of the ridge. Five of these isolated 

 crests, the bases of the future Unlets, can be counted on the dorsum. 

 The anal fin region is not so well preserved. The ridges terminate at a 

 point considerably anterior to the caudal fin. The embryonic marginal 

 fin is continuous, but much collapsed in the present state of the 

 specimen. A slight dorsal ridge about half-way from the shoulder 

 to the level of the anus perhaps represents the first dorsal, but is by no 

 means distinct. The black pigment is very similar in distribution to 

 the last stage ; but the dorsal post-anal chromatophores are larger and 

 more numerous, forming a practically continuous line on either side of 

 the ridge of the second dorsal and its finlets. 



A badly -preserved specimen of about 13 mm. differs from the last 

 chiefly in the greater length and more pointed contour of the snout, and 

 in the elonG;ation of the abdominal region. It forms a transitional 

 stage to the more advanced condition shown in Figures 3 and 4. Fig. 3 

 is drawn from an example about 14 mm. in length, viewed as an 

 opaque object ; it is somewhat shorter and deeper than the specimen of 

 about 18 mm. shown in Fig. 4, but the stage of development seems to 

 be about the same. The bones of the head are well defined. There 

 are no cephalic spines, but a strong longitudinal ridge at the upper 

 extremity of the gill-cover may represent a part of the spinous 

 armature of the young Naucratcs. The outline of the head in Fig. 3 

 is probably unnatural, since three out of four specimens at about the 

 same stage have the convex antero-superior profile of Fig. 4. The jaws 

 are sub-equal, but the upper projects slightly, and is furnished with 

 a pair of hooked teeth quite outside the gape. The general conforma- 

 tion can be gathered from the figures, the body being laterally 

 compressed, but not more so than usual in young fish of similar stages. 

 So far as I can gather from the examination of my material, tlie natural 

 condition of the dorsal and anal fins is shown in Fig. 4. In frayed 

 examples the finlets appear separated, but I am satisfied that the 

 marginal fin really extends without any serious break in its outline 

 from the first dorsal to the end of the dorsal series of finlets, and 

 ventrally from the anus to the end of the anal finlets. It does not 

 appear to be continuous, either dorsally or ventrally, with the caudal 



