SOLENOSTOMA. 
105 
front of the eyes. A triradiate osseous flange occurs on the basis 
of the pectoral fin, consisting of the sector of a circle and three radii 
meeting at a point; there is a spine with a papilla at the end of each 
radius and at the point of intersection of the radii. (Fig. 2.) 
The total length from the tip of the snout to the end of the middle 
caudal rays is 81 mm.; to the base of the caudal fin, 65 mm.; length 
of snout (from anterior border of eye), 20 mm.; height of snout in 
the middle of its length, 3 mm. ; length of base of second dorsal, 
about 6 • 5 mm. ; length of caudal peduncle from the end of the second 
dorsal to the base of the middle caudal ray, about 7 mm. 
Fig. 2.—Surface view of the basis of a pectoral fin, showing the 
appearance of the dermal scute and papillae. 
The drawings of eggs and larvse on Plate I. bring out the fact, 
mentioned above, that the brood-pouch contains eggs and young 
at very different stages of development. This is unusual amongst 
brood-nursing fishes, and is obviously connected with the circum¬ 
stance, first ascertained by Dr. Guenther,* that in the case of the 
Solenostomidse it is the female which carries the eggs during the 
period of incubation, whereas in the allied family of the Syngnathi- 
dse the male performs this office ;f but the pouch of the female 
Solenostomid is not homologous with that of the male Syngnathid. 
The clear eggs in the pouch measure about half a millimetre in 
diameter ; the developed eggs 1 mm. The embryo grows to such a 
length that its body becomes twice wound round the amber-coloured 
yolk ; and the eyes become darkly pigmented while still within the 
egg-membrane. The hatchling (Fig. 3) possesses a pair of small 
pectoral fins, but no ventrals; the head is bent at right angles to the 
body, its lower surface being attached to the front wall of the yolk- 
* Op. cit. (Fishes of Zanzibar). 
•j* Dr. G. Duncker (Syngnathiden-Studien. Jahrb. Hamburg. Wissensch. 
Anstalten, XXV., Beiheft 2, 1908, p. 63) states that in several species of Syng- 
nathus and Hippocampus a rudimentary brood-pouch appears as a rather 
frequent abnormality in female individuals. This work should be consulted 
for data relating to variation in number of rays in the dorsal fin, in the pro¬ 
portion of height to length of the snout, and in other characters of the genu* 
Siphonostoma. 
