TRANSACTIONS OF SECTION D. 697 



the autumn of 1902 thirty-three species, viz. Tlolotburoidea 8, OrinoiJea 1, 

 Asteroidea 11, Ophiuroidea 7, and Ecliinoidea G, the most common genus 

 of each of these orders being !Sipiapta, Antedon, Asterias, Ophiocoma, and Echinus. 

 Note was taken of the very considerable variations in the shape of the test of 

 Echiints esculentus and in the number of arms of certain of tlie Asteroidea. 



The remaining part of tbe paper was taken up with a discussion on the 

 •variation o'i Ophiocoma niijra (O. F. MUller), and an account was given of the 

 results obtained from an examination of certain external features of 3,000 

 specimens of tliis Brittle-star. An attempt was made by means of diagrams 

 to classify the shape and colour variations of tlie disc. It was found" that 

 the disc tends to become circular in the more fully developed animals, but 

 that it is in general pentagonal and not round. Twenty-four per cent, showed no 

 colour variation, while 64 per cent, had a pentagonal yellowish central disc 

 marking. In 12 per cent, of cases this marking was small and circular. The 

 correlation between arm-length and disc-breadth was worked out by the methods 

 followed in 'Biometrika,' and a table was given showing the number of animals 

 having a certain disc-breadth associated with a certain arm-length. The equation 

 to the * Line of Kegression ' of arm-length on disc-breadth was 



y = 4-8962ai.' + 1 '17469962, 



and this was shown by means of a diagram to represent very closely the observed 

 facts. The mean disc-breadth and arm-length were respectivelv 10-106 mm. and 

 50-656 mm., a relationship which is very noteworthy in view 'of the important 

 part which the number^i-e plays in tbe arrangement of the organs of the Echino- 

 dermata. A ' Polygon of Frequency ' based on the disc-breadth was given, and 

 also the curve whose equation is 



;/=i8o-57(i— i^ y''^% f i+__z„r-^"' 



V 9-3264/ V 2U-9913/ 



which best fits it. Tables were added showing that -13 per cent, had more than 

 one madreporic plate, and that out of 3,000 specimens thirteen had an abnormal 

 number of rays, there being one Brittle-star with only four arms and twelve 

 with six arms each. 



7. JS^ote on the Eggs of the Shanny (Blennius pholis, L.). 

 By Professor W. C. McIntosh, M.D., F.R.S. 



In the life-histories of the British food-fishes, published by Dr. Masterman and 

 the author in 1897, it is stated that the eggs of this fish had not hitherto received 

 satisfactory attention. In June of this year an adult female, 4| inches in length, 

 was captured with enlarged ovaries. On the morning of June 5 it was found to 

 have discharged a number of golden eggs, each having a faintlv pinkish disc for 

 fixing it to stones and other surfaces. As attached to glass, each i^gn^ was circular 

 in outline with a distinct hyaline zona, the contents being dull pinkish or pale 

 salmon. This tint was enlivened by a series of bright yellow granules and masses 

 (oil-globules). The egcr formed an oblate spheroid, the vertical diameter being 

 •7630 mm., whilst the transverse diameter ranged from 1-1811 mm. to 1-2192 mm. 

 The breadth of the pale pinkish rim for attachment was about -3048 mm. Many 

 of the discs had a finished appearance, whilst in others tbe edge was spongy, with 

 projecting processes. In minute structure the whole is granular. Allusion is 

 made to the observations of Dr. Scharff on the structure of the peculiarly modified 

 ovarian follicle of the shanny and the remarkable hardihood of the fish, which 

 can be kept for a week at least in fresh water. The proportion of males and 

 females is also mentioned. The food of the shanny at St. Andrews largely con- 

 sists of the stunted email and young mussels, Balani, small univalves, such as 

 young Littorinae and adult Rissoae, with fragments of limpet. 



