50 A. E. HEFFOED. 



niidibranch Calma glaucoidcs and a batch of its eggs were also occupy- 

 ing the valve, and it seems probable, if not certain, that the fish-eggs 

 had been devoured by the nudibranch, which has been recorded as 

 commonly occurring associated with Goby and Blenny eggs, and vary- 

 ing in colour so as to resemble the eggs which it apparently preys 

 upon.* 



Quite recently — viz. on 17th February, 1910, and after this paper 

 was in manuscript — I have secured an early batch of Lepadogaster 

 himacidatus eggs. On this occasion I took particular care to examine 

 the accompanying parent fisli so as to make sure of its identity as 

 distinct from L. microcepliahis, a closely similar species first dis- 

 tinguished by Brook,f whose description, however, I have not yet 

 been able to see. Ehrenbaum (5b, p. 121) gives as the distinctive 

 fin-ray formula for L. microcqjhalns D = 5, A = 6, C = 17-19 ; while Day 

 gives for L. bimaculatus D=^5-7, A = 4-6, C = 12. My specimen has 

 clearly six dorsal fin-rays and not more than four or five anal fin-rays, 

 which precludes X. microcephalus, while in its general appearance it 

 resembled the common two- spotted sucker, L. himacidatus. It was 

 not possible to count the caudal rays, as it was desired to keep the 

 specimen alive and uninjured. Two of the eggs had the following 

 dimensions : — Oval outline of egg-capsule, as seen from above, 

 measured in one case 1*44 x 1*24 mm. and in the other 1*54 x 1*22 mm. 

 The height of the capsule was respectively 62 and 0'70 mm. The 

 sizes closely approximate to those noted the previous summer, and in 

 following through the development from pre-embryonic to larval 

 stages, the characters proved to be identical, save for very slight 

 variation in pigmentation. 



The ovoidal inferiorly truncated egg-capsule and its peculiar basal 

 attachment disc and filaments have been minutely described by Holt 

 {op. cit.). I noted that as a rule the eggs in one batch showed several 

 stages of development, indicating that they were deposited intermittently. 

 In the earliest stages the finely granular yolk is quite colourless and 

 translucent, and carries a single oil-globule of about 0'25 to 0*28 mm. 

 diameter, which has a slightly darker appearance than the yolk and is 

 at first the most conspicuous content of the egg. The embryo almost 

 invariably occupies a horizontal position in the egg. Black pigment 

 appears on the body soon after the outgrowth of the caudal rudiment, 

 and soon forms a dense and continuous line along the ventro-lateral 

 region from immediately behind the pectoral fins to within a short 

 distance of the caudal tip. Anteriorly pigment is sparse, only a few 



* See Joirni. M.B.A., N.S., Yol. VII, p. 280. 



t Brook, G., Froc. Roy. PJu/s. Soc. 3/ in., Vol. X, Pt. 1, p. 166. 



