122 NOTES ON THE REPRODUCTION OF TELEOSTEAN FISHES 



Blennius ocellaris. Linn. Butterfly blenny. 



Cunningham, .1. T., Journ. M. B. Assoc, N.S., i., 1891, p. 36, Fig. XXV. Egg. 

 Holt, E. W. L., Ajin. Mas. Marseille, v., 1898, Fasc. II. Xcidy hatched aiul 

 late pelagic larva. 



This blenny must probably be regarded as difficult to catch rather 

 than as actually rare in the Plymouth district. Two adults, both 

 males, were taken in 1897. Cunningham has already described the 

 ova, which were found in an ox-bone, and identified by the presence 

 of the male parent. 



On the 20th June, 1896, Mr. Beaumont dredged a large whelk-shell 

 off the Plymouth Mewstone. In the mouth of the shell was a male 

 Butterfly blenny, guarding a great number of eggs. Higher up in 

 the shell a Lcpadogastcr himaculatus was similarly occupied. I did 

 not specially examine the eggs of the blenny, but Guitel's researches 

 {Arch. Zool. ExiHv., S. iii., I., 1893, p. 325) render it very probable that 

 in this species, as in others, the egg adheres by means of a series of 

 long attachment filaments situate around the micropyle. The eggs 

 were in various advanced stages of development, and many had hatched 

 before the Busy Bee arrived at the Laboratory, but some had not 

 hatched on the following day. Very probably they had not all been 

 spawned at the same time. All unhatched eggs appeared bright red, 

 the colour being that of the yolk. 



A larva, from twelve to twenty-four hours old, measures 6-30 mm., 

 of which the greater part is occupied by the tail. The distance 

 between the snout and the hind end of the yolk is only 1-85 mm., and 

 of this •95 mm. pertains to the head. The rectum occurs immediately 

 behind the yolk. The head is bluntly rounded in contour, and the 

 edses of the marginal tins show a bold inflection towards the end 

 of the tail, the caudal part being spatulate. The pectoral fin is large, 

 with well-developed rays, the longest of which, when laid parallel to 

 the body, extend •12 mm. beyond the anus. This fin is yellow, with 

 black chromatophores along the rays. The brain and anterior tissues 

 generally are buff by transmitted light. Black chromatophores occur 

 on the top of the head and about the posterior end of the trunk. 

 The marginal fins are devoid of pigment. The notochord is multi- 

 columnar. 



I was unable to study any later stages as an accident to the escape 

 pipe caused the loss of all my material. The larvce appeared delicate, 

 since many died soon after hatching; but as they were exceedingly 

 active it is quite possible that they injured themselves against the sides 

 of the bell-jar in which they were confined. 



A much more advanced larva, taken in the little bay under Professor 

 Marion's laboratory, at Endourae, appears to belong to the species now 



