156 



ECHINOIDEA. II. 



St. 6 (63 43' Lat. N. 14 34' Long. W. 90 fathoms 7°oC. Bottom temp.) 1 specimen. 



- 8 (63° 56' - 24 40' 136 - - ) 1 



— 85 (63°2i' — 25°2i' — 170 — ) I 



Br. lyrifera is very common in the European Seas, from Northern Norway and Iceland 

 (the South Coast) to the Mediterranean. It is further stated to occur at the Cape of Good Hope and 

 in the American Seas, from Greenland to the West Indies. The bathymetrieal distribution is stated to 

 be from shallow water to 2435 fathoms. — This wide geographical and bathymetrieal distribution 

 looks somewhat suspicious, the more so, as the species is said to be very variable. A close examina- 

 tion shows that the great variation» is mainly due to different species having been confounded, and 

 the wide geographical and bathymetrieal distribution of Br lyrifera must be considerably restricted. 



The Mediterranean form of Br. lyrifera has been described as a distinct species (Brissus) pul- 

 vinatus by Phi lip pi (Op. cit), evidently without knowledge of the < Brissus lyrifera described by 

 Forbes (1841). All later authors agree in uniting Br. pufoinaius with lyrifera, and probably they are 

 right herein, though certain differences can be pointed out as distinguishing the Mediterranean from 

 the northern form. The specimens from the Mediterranean are generally more elongate, and especially 

 the posterior end of the test is more vertical than in the northern form and a little hollowed. The 

 posterior petals are a little more parallel than in the northern form, and the figure formed by the 

 peripetalous fasciole is somewhat narrower. The odd anterior ambulacrum is narrower and its sides 

 more vertical than in the northern form. When comparing specimens from the Mediterranean with 

 specimens from the Skagerrak the difference is very considerable (PI. III. Figs. 12, 20, 23 and PL IV. 

 Fig. 9 — comp. with PI. III. Figs. 3, 18, 21— 22, further PI. IV. Figs. 2 — 3, 16, comp. with PL IV. Figs. 14 

 — 15, 17); but these, evidently, are the extreme forms. All transitional forms may be found, and speci- 

 mens of both forms may occur in the same locality; I have both forms from Bergen and from the 

 Bay of Biscay. Other more reliable characters in the structure of the test, by which they might be 

 distinguished, I have been unable to find, nor are reliable characters found in the pedicellarise, though 

 thev are upon the whole more slender in the Mediterranean form. All the specimens from the Medi- 

 terranean, which I have seen, are white, whereas all the specimens of the northern form, with a very 

 few exceptions, are dark coloured. If this is the case also in the living specimens and does not depend 

 on the preservation, it is certainly a difference worth noticing, and in that case I would think it right 

 to distinguish the Mediterranean form as a variety of lyrifera, var. pulvinata. I can only state, that 

 all the very numerous living specimens of the northern form of lyrifera which I have seen, were 

 dark brownish. 



What the Brissopsis par/ua Val. named by Perrier (Rech. s. les pedicellaires p. 174) really is, 

 cannot be settled, the type specimen not being found any longer in the Paris Museum. Since, how- 

 ever, it has (according to a communication from Professor E. Perrier) come from Stockholm (through 

 Malm), it can scarcely be doubted that Agassiz was right in making it a synonym of lyrifera. At 

 any rate we must be satisfied with the statement. 



The occurrence of Br issopsis lyrifera at the Cape of Good Hope was first recorded in the .Chal- 

 lenger -Echinoidea (St. 141, 142; Simons Bay, Agulhas Bank), Agassiz (Op. cit. p. 189) stating that he 

 was unable to distinguish specimens of this genus collected at St. 142 from Brissopsis lyrifera except by 



