MUSEUM OF COMPARATIVE ZOOLOGY. 257 



flatness of the abactinal part of the test, and the great development of the 

 abactinal system, remind us of some forms of Hemipedina, as, for instance, 

 Heinipedina Guerangeri Cott. et Trig. The actinal opening is large, with 

 sharp cuts for the passage of long, narrow gills. The spines are long, mod- 

 erately stout, as long as the diameter of the test, longitudinally striated, 

 resembling the spines of some species of Hemipedina figured by Wright. 

 The pores are arranged in connected vertical arcs, of three to four pairs. 

 There are two rows of perforate primary tubercles in the ambulacral area, 

 decreasing rapidly in size towards apex, and placed close together. They 

 are somewhat smaller than those of the intcrambulacral area. There are 

 one or two small imperforate tubercles at the base of the larger ones. The 

 poriferous zone is broad and well defined, spreading slightly at actinostome. 

 The perforate interambulacral tubercles are arranged in two primary rows, 

 separated from the poriferous zone by a row of small imperforate tubercles, 

 with two or three similar irregular rows between the larger tubercles 

 in the median interambulacral zone. The plates of the abactinal sys- 

 tem are large, with straight sides, the genital are heptagonal, carrying 

 five to six small tubercles, and as many still smaller ones. The ocular 

 plates are pentagonal, with a large ocular pore surrounded by an arc of 

 small tubercles. The plates covering the large anal system are very 

 numerous and minute. The anus is situated in the very centre. The 

 teeth resemble those of Echinocidaris. The buccal membrane is strength- 

 ened round the mouth, close to the teeth, by ten large plates (perforated 

 for buccal tentacles), occupying nearly the whole membrane, with eight to 

 ten very much smaller ones between the large plates and test. The color 

 of the large spines is of a dull yellowish green, while the smaller spines, 

 as well as test and abactinal plates, have a more yellowish tint. 

 From 138 to 270 fathoms. 



Echinocidaris punctulata Desml., feud. Echin. 



Syn. Echinocidaris punctulata A. Ac, Bull. M. C. Z., No. 2. 

 " " Davisii A. Ac " " " 



" " punctulata Lutk., Bid. til Kunds. om Echin. 

 " " Holmes, P. F. PI. 2, fig. 5. 

 Anapcsus carolinus Holmes, P. P. F. PI. 2, fig. 2. 



The specimens collected by Mr. Pourtales seem to show conclusively 

 that the species distinguished as E. Davisii in the second number of this 

 Bulletin is only a local variety. All Echinocidaridae are difficult to distin- 

 guish, as there is great variation in the same species, in the number and 

 arrangement of the tubercles ; and the characters by which E. Davisii was 

 separated from E. punctulata are found in the large series of young speci- 

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