106 
SPOLIA ZEYLANICA. 
sac. In the next stage (Fig. 4) the head is released from the yolk- 
sac, and is beginning to bend forwards. In the following stage the 
head has nearly attained its definitive horizontal position and the 
elongation of the snout has commenced ; at the same time there is a 
characteristic gular projection below (Fig. 5). In the latest stage 
seen by me (Fig. 6) there are still no ventral fins, and the embryonic 
median fin-fold retains its normal proportions. The segmental 
papillae, already present in the hatchling, are now very distinct. 
I observed two rows on each side, a dorso-lateral and a ventro-lateral 
row; in the example figured there were 31 dorso-lateral papillae ; 
between the vent and the caudal expansion of the embryonic fin 
there were 13 dorso-lateral and 13 ventro-lateral papillae. The first 
dorso-lateral papilla lies behind the humeral arch, the first ventro¬ 
lateral over the pyloric complex. These segmental papillae are 
present in other larval or post-larval Lophobranchiate fishes, and do 
not correspond with the laciniations of the adult fish,* of which 
there is no trace at this stage ; their position near the dorsal and 
ventral ends of the myotomes may correspond with the distribution 
of the rami cutanei dor sales and ventrales respectively, and if this is • 
so they could be regarded as segmental receptors. 
The cartilages of the head can be seen with great clearness through 
the transparent integument (Fig. 6). Their disposition accords in 
general with that of larval pipe-fishes, f A marked feature of the 
larvse of Solenostoma is the apparent occlusion of the branchial 
apparatus so far as the external view is concerned. The pigment on 
the body and fin-fold is confined to small groups of cells as shown in 
the figures. There is a special pigment-group at the base of the 
pectoral fin, and another on the pyloric complex (Fig. 6). There is 
still no sign of the definitive median fins, although the yolk-sac has 
been used up. 
In conclusion it may be pointed out that S. lacmiatum seems to 
afford an instance of the combination of warning colouration and 
protective laciniation such as is rarely met with amongst fishes. 
* They correspond with the spines of the adult, at least in part, 
j Cf. H. H. Swinnerton. Morphology of Teleostean Head Skeleton. Quart. 
Journ. Micro. Sop,, Vol. 45, 1901, see pp. 537 and 554 and PI. 31, fig. 48 
(. Siphonostoma ). 
