568 
BULLETIN OP THE BUREAU OF FISHERIES 
The newly hatched fish, 1 .2 mm long— The following account of the newly hatched 
fish has been compiled from Kuntz’s description (loc. cit.) based on a fresh specimen: 
It is exceedingly delicate, and only about 1.2 mm long. It is highly transparent and 
marked by small areas of delicate yellow pigment on the dorsal surface of the head, 
over the vent and with a vertical band about half way from the vent to the tip of the 
tail. The vent is located slightly in advance of midbody length. The dorsal and 
ventral finfolds are continuous and the depth of each fold is equal to or greater than 
the depth of the body posterior to the vent (fig. 65). 
Figure 65 .—Gobionellus boleosoma. From newly hatched fish, length 1.2 mm. (Drawn by Effie B. Decker. After Kuntz.) 
Kuntz was able to keep the delicate larvae alive in the laboratory only a few 
hours, and he did not have any advanced larval stages. Descriptions and illustra- 
tions of the subsequent development of the young are based on preserved specimens 
contained in the collection studied by the present writers. 
Specimens 2.5 mm long. — The larvae of this genus are extremely slender and this 
character generally distinguishes them from those of Gobiosoma and Microgobius. 
The caudal portion of the body is especially slender and at this size notably longer 
than the rest of the body. The head is rather broad, its width being nearly as great 
as its depth; the mouth is almost vertical and very close in front of the moderately 
large protruding eyes. The air bladder is plainly visible as a round or slightly elon- 
gate clear area within the abdominal cavity; dorsally of the air bladder the dark 
peritoneum is visible (and at a slightly larger size the black peritoneum at this point 
becomes very pronounced and forms a recognition mark). Fins are undeveloped, 
except for a slight indication of rays in the fin fold around the tip of the notochord 
(fig. 66). 
Specimens 3.5 mm long. — The fish has become only slightly more robust than it 
was at a length of 2.5 mm. The mouth remains very close to the eyes, but has become 
slightly less vertical. Pectoral fins have appeared as tufts of membrane without 
rays. The notochord remains straight, with indications of rays around its tip. The 
soft dorsal and anal bases are in part evident, but no definite rays have developed. 
On some specimens a few very small dark spots are present along the ventral outline 
of the body and tail. The black peritoneum over the air bladder is moderately 
distinct and has acquired a crescent shape which is characteristic of the young of this 
species (fig. 67). 
Specimens 5.0 mm long. — Little change has taken place in the shape of the head 
and body since a length of 3.5 mm was attained. The mouth has become slightly 
